9079 Commits

Author SHA1 Message Date
Sean Christopherson
c482f2cebe KVM: x86: Move APIC access page helper to common x86 code
Move the APIC access page allocation helper function to common x86 code,
the allocation routine is virtually identical between APICv (VMX) and
AVIC (SVM).  Keep APICv's gfn_to_page() + put_page() sequence, which
verifies that a backing page can be allocated, i.e. that the system isn't
under heavy memory pressure.  Forcing the backing page to be populated
isn't strictly necessary, but skipping the effective prefetch only delays
the inevitable.

Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230106011306.85230-10-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-01-13 10:45:25 -05:00
Sean Christopherson
1459f5c6b8 KVM: x86: Handle APICv updates for APIC "mode" changes via request
Use KVM_REQ_UPDATE_APICV to react to APIC "mode" changes, i.e. to handle
the APIC being hardware enabled/disabled and/or x2APIC being toggled.
There is no need to immediately update APICv state, the only requirement
is that APICv be updating prior to the next VM-Enter.

Making a request will allow piggybacking KVM_REQ_UPDATE_APICV to "inhibit"
the APICv memslot when x2APIC is enabled.  Doing that directly from
kvm_lapic_set_base() isn't feasible as KVM's SRCU must not be held when
modifying memslots (to avoid deadlock), and may or may not be held when
kvm_lapic_set_base() is called, i.e. KVM can't do the right thing without
tracking that is rightly buried behind CONFIG_PROVE_RCU=y.

Suggested-by: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230106011306.85230-9-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-01-13 10:45:24 -05:00
Sean Christopherson
e0bead97e7 KVM: SVM: Don't put/load AVIC when setting virtual APIC mode
Move the VMCB updates from avic_refresh_apicv_exec_ctrl() into
avic_set_virtual_apic_mode() and invert the dependency being said
functions to avoid calling avic_vcpu_{load,put}() and
avic_set_pi_irte_mode() when "only" setting the virtual APIC mode.

avic_set_virtual_apic_mode() is invoked from common x86 with preemption
enabled, which makes avic_vcpu_{load,put}() unhappy.  Luckily, calling
those and updating IRTE stuff is unnecessary as the only reason
avic_set_virtual_apic_mode() is called is to handle transitions between
xAPIC and x2APIC that don't also toggle APICv activation.  And if
activation doesn't change, there's no need to fiddle with the physical
APIC ID table or update IRTE.

The "full" refresh is guaranteed to be called if activation changes in
this case as the only call to the "set" path is:

	kvm_vcpu_update_apicv(vcpu);
	static_call_cond(kvm_x86_set_virtual_apic_mode)(vcpu);

and kvm_vcpu_update_apicv() invokes the refresh if activation changes:

	if (apic->apicv_active == activate)
		goto out;

	apic->apicv_active = activate;
	kvm_apic_update_apicv(vcpu);
	static_call(kvm_x86_refresh_apicv_exec_ctrl)(vcpu);

Rename the helper to reflect that it is also called during "refresh".

  WARNING: CPU: 183 PID: 49186 at arch/x86/kvm/svm/avic.c:1081 avic_vcpu_put+0xde/0xf0 [kvm_amd]
  CPU: 183 PID: 49186 Comm: stable Tainted: G           O       6.0.0-smp--fcddbca45f0a-sink #34
  Hardware name: Google, Inc. Arcadia_IT_80/Arcadia_IT_80, BIOS 10.48.0 01/27/2022
  RIP: 0010:avic_vcpu_put+0xde/0xf0 [kvm_amd]
   avic_refresh_apicv_exec_ctrl+0x142/0x1c0 [kvm_amd]
   avic_set_virtual_apic_mode+0x5a/0x70 [kvm_amd]
   kvm_lapic_set_base+0x149/0x1a0 [kvm]
   kvm_set_apic_base+0x8f/0xd0 [kvm]
   kvm_set_msr_common+0xa3a/0xdc0 [kvm]
   svm_set_msr+0x364/0x6b0 [kvm_amd]
   __kvm_set_msr+0xb8/0x1c0 [kvm]
   kvm_emulate_wrmsr+0x58/0x1d0 [kvm]
   msr_interception+0x1c/0x30 [kvm_amd]
   svm_invoke_exit_handler+0x31/0x100 [kvm_amd]
   svm_handle_exit+0xfc/0x160 [kvm_amd]
   vcpu_enter_guest+0x21bb/0x23e0 [kvm]
   vcpu_run+0x92/0x450 [kvm]
   kvm_arch_vcpu_ioctl_run+0x43e/0x6e0 [kvm]
   kvm_vcpu_ioctl+0x559/0x620 [kvm]

Fixes: 05c4fe8c1bd9 ("KVM: SVM: Refresh AVIC configuration when changing APIC mode")
Cc: stable@vger.kernel.org
Cc: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230106011306.85230-8-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-01-13 10:45:24 -05:00
Sean Christopherson
f651a00895 KVM: x86: Don't inhibit APICv/AVIC if xAPIC ID mismatch is due to 32-bit ID
Truncate the vcpu_id, a.k.a. x2APIC ID, to an 8-bit value when comparing
it against the xAPIC ID to avoid false positives (sort of) on systems
with >255 CPUs, i.e. with IDs that don't fit into a u8.  The intent of
APIC_ID_MODIFIED is to inhibit APICv/AVIC when the xAPIC is changed from
it's original value,

The mismatch isn't technically a false positive, as architecturally the
xAPIC IDs do end up being aliased in this scenario, and neither APICv
nor AVIC correctly handles IPI virtualization when there is aliasing.
However, KVM already deliberately does not honor the aliasing behavior
that results when an x2APIC ID gets truncated to an xAPIC ID.  I.e. the
resulting APICv/AVIC behavior is aligned with KVM's existing behavior
when KVM's x2APIC hotplug hack is effectively enabled.

If/when KVM provides a way to disable the hotplug hack, APICv/AVIC can
piggyback whatever logic disables the optimized APIC map (which is what
provides the hotplug hack), i.e. so that KVM's optimized map and APIC
virtualization yield the same behavior.

For now, fix the immediate problem of APIC virtualization being disabled
for large VMs, which is a much more pressing issue than ensuring KVM
honors architectural behavior for APIC ID aliasing.

Fixes: 3743c2f02517 ("KVM: x86: inhibit APICv/AVIC on changes to APIC ID or APIC base")
Reported-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Cc: stable@vger.kernel.org
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230106011306.85230-7-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-01-13 10:45:23 -05:00
Sean Christopherson
a58a66afc4 KVM: x86: Don't inhibit APICv/AVIC on xAPIC ID "change" if APIC is disabled
Don't inhibit APICv/AVIC due to an xAPIC ID mismatch if the APIC is
hardware disabled.  The ID cannot be consumed while the APIC is disabled,
and the ID is guaranteed to be set back to the vcpu_id when the APIC is
hardware enabled (architectural behavior correctly emulated by KVM).

Fixes: 3743c2f02517 ("KVM: x86: inhibit APICv/AVIC on changes to APIC ID or APIC base")
Cc: stable@vger.kernel.org
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230106011306.85230-6-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-01-13 10:45:23 -05:00
Sean Christopherson
5aede752a8 KVM: SVM: Process ICR on AVIC IPI delivery failure due to invalid target
Emulate ICR writes on AVIC IPI failures due to invalid targets using the
same logic as failures due to invalid types.  AVIC acceleration fails if
_any_ of the targets are invalid, and crucially VM-Exits before sending
IPIs to targets that _are_ valid.  In logical mode, the destination is a
bitmap, i.e. a single IPI can target multiple logical IDs.  Doing nothing
causes KVM to drop IPIs if at least one target is valid and at least one
target is invalid.

Fixes: 18f40c53e10f ("svm: Add VMEXIT handlers for AVIC")
Cc: stable@vger.kernel.org
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230106011306.85230-5-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-01-13 10:45:22 -05:00
Sean Christopherson
0ccf3e7cb9 KVM: SVM: Flush the "current" TLB when activating AVIC
Flush the TLB when activating AVIC as the CPU can insert into the TLB
while AVIC is "locally" disabled.  KVM doesn't treat "APIC hardware
disabled" as VM-wide AVIC inhibition, and so when a vCPU has its APIC
hardware disabled, AVIC is not guaranteed to be inhibited.  As a result,
KVM may create a valid NPT mapping for the APIC base, which the CPU can
cache as a non-AVIC translation.

Note, Intel handles this in vmx_set_virtual_apic_mode().

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20230106011306.85230-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-01-13 10:45:22 -05:00
Sean Christopherson
97a71c444a KVM: x86: Purge "highest ISR" cache when updating APICv state
Purge the "highest ISR" cache when updating APICv state on a vCPU.  The
cache must not be used when APICv is active as hardware may emulate EOIs
(and other operations) without exiting to KVM.

This fixes a bug where KVM will effectively block IRQs in perpetuity due
to the "highest ISR" never getting reset if APICv is activated on a vCPU
while an IRQ is in-service.  Hardware emulates the EOI and KVM never gets
a chance to update its cache.

Fixes: b26a695a1d78 ("kvm: lapic: Introduce APICv update helper function")
Cc: stable@vger.kernel.org
Cc: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Cc: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230106011306.85230-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-01-13 10:45:22 -05:00
Sean Christopherson
0a19807b46 KVM: x86: Blindly get current x2APIC reg value on "nodecode write" traps
When emulating a x2APIC write in response to an APICv/AVIC trap, get the
the written value from the vAPIC page without checking that reads are
allowed for the target register.  AVIC can generate trap-like VM-Exits on
writes to EOI, and so KVM needs to get the written value from the backing
page without running afoul of EOI's write-only behavior.

Alternatively, EOI could be special cased to always write '0', e.g. so
that the sanity check could be preserved, but x2APIC on AMD is actually
supposed to disallow non-zero writes (not emulated by KVM), and the
sanity check was a byproduct of how the KVM code was written, i.e. wasn't
added to guard against anything in particular.

Fixes: 70c8327c11c6 ("KVM: x86: Bug the VM if an accelerated x2APIC trap occurs on a "bad" reg")
Fixes: 1bd9dfec9fd4 ("KVM: x86: Do not block APIC write for non ICR registers")
Reported-by: Alejandro Jimenez <alejandro.j.jimenez@oracle.com>
Cc: stable@vger.kernel.org
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230106011306.85230-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-01-13 10:45:21 -05:00
Vitaly Kuznetsov
4e5bf89f27 KVM: x86: Hyper-V invariant TSC control
Normally, genuine Hyper-V doesn't expose architectural invariant TSC
(CPUID.80000007H:EDX[8]) to its guests by default. A special PV MSR
(HV_X64_MSR_TSC_INVARIANT_CONTROL, 0x40000118) and corresponding CPUID
feature bit (CPUID.0x40000003.EAX[15]) were introduced. When bit 0 of the
PV MSR is set, invariant TSC bit starts to show up in CPUID. When the
feature is exposed to Hyper-V guests, reenlightenment becomes unneeded.

Add the feature to KVM. Keep CPUID output intact when the feature
wasn't exposed to L1 and implement the required logic for hiding
invariant TSC when the feature was exposed and invariant TSC control
MSR wasn't written to. Copy genuine Hyper-V behavior and forbid to
disable the feature once it was enabled.

For the reference, for linux guests, support for the feature was added
in commit dce7cd62754b ("x86/hyperv: Allow guests to enable InvariantTSC").

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221013095849.705943-4-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-28 06:08:22 -05:00
Vitaly Kuznetsov
24652b741c KVM: x86: Add a KVM-only leaf for CPUID_8000_0007_EDX
CPUID_8000_0007_EDX may come handy when X86_FEATURE_CONSTANT_TSC
needs to be checked.

No functional change intended.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221013095849.705943-3-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-28 06:08:19 -05:00
Sean Christopherson
94fbbfbbdf KVM: x86/mmu: Pivot on "TDP MMU enabled" when handling direct page faults
When handling direct page faults, pivot on the TDP MMU being globally
enabled instead of checking if the target MMU is a TDP MMU.  Now that the
TDP MMU is all-or-nothing, if the TDP MMU is enabled, KVM will reach
direct_page_fault() if and only if the MMU is a TDP MMU.  When TDP is
enabled (obviously required for the TDP MMU), only non-nested TDP page
faults reach direct_page_fault(), i.e. nonpaging MMUs are impossible, as
NPT requires paging to be enabled and EPT faults use ept_page_fault().

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221012181702.3663607-8-seanjc@google.com>
[Use tdp_mmu_enabled variable. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-27 06:03:02 -05:00
Sean Christopherson
f2e4535c27 KVM: x86/mmu: Pivot on "TDP MMU enabled" to check if active MMU is TDP MMU
Simplify and optimize the logic for detecting if the current/active MMU
is a TDP MMU.  If the TDP MMU is globally enabled, then the active MMU is
a TDP MMU if it is direct.  When TDP is enabled, so called nonpaging MMUs
are never used as the only form of shadow paging KVM uses is for nested
TDP, and the active MMU can't be direct in that case.

Rename the helper and take the vCPU instead of an arbitrary MMU, as
nonpaging MMUs can show up in the walk_mmu if L1 is using nested TDP and
L2 has paging disabled.  Taking the vCPU has the added bonus of cleaning
up the callers, all of which check the current MMU but wrap code that
consumes the vCPU.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221012181702.3663607-9-seanjc@google.com>
[Use tdp_mmu_enabled variable. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-27 06:03:01 -05:00
Sean Christopherson
aeb568a1a6 KVM: x86/mmu: Replace open coded usage of tdp_mmu_page with is_tdp_mmu_page()
Use is_tdp_mmu_page() instead of querying sp->tdp_mmu_page directly so
that all users benefit if KVM ever finds a way to optimize the logic.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221012181702.3663607-10-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-27 06:03:01 -05:00
David Matlack
362871d74f KVM: x86/mmu: Rename __direct_map() to direct_map()
Rename __direct_map() to direct_map() since the leading underscores are
unnecessary. This also makes the page fault handler names more
consistent: kvm_tdp_mmu_page_fault() calls kvm_tdp_mmu_map() and
direct_page_fault() calls direct_map().

Opportunistically make some trivial cleanups to comments that had to be
modified anyway since they mentioned __direct_map(). Specifically, use
"()" when referring to functions, and include kvm_tdp_mmu_map() among
the various callers of disallowed_hugepage_adjust().

No functional change intended.

Signed-off-by: David Matlack <dmatlack@google.com>
Reviewed-by: Isaku Yamahata <isaku.yamahata@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20220921173546.2674386-11-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-27 06:03:01 -05:00
David Matlack
1290f90e77 KVM: x86/mmu: Stop needlessly making MMU pages available for TDP MMU faults
Stop calling make_mmu_pages_available() when handling TDP MMU faults.
The TDP MMU does not participate in the "available MMU pages" tracking
and limiting so calling this function is unnecessary work when handling
TDP MMU faults.

Signed-off-by: David Matlack <dmatlack@google.com>
Reviewed-by: Isaku Yamahata <isaku.yamahata@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20220921173546.2674386-10-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-27 06:03:00 -05:00
David Matlack
a158127f55 KVM: x86/mmu: Split out TDP MMU page fault handling
Split out the page fault handling for the TDP MMU to a separate
function.  This creates some duplicate code, but makes the TDP MMU fault
handler simpler to read by eliminating branches and will enable future
cleanups by allowing the TDP MMU and non-TDP MMU fault paths to diverge.

Only compile in the TDP MMU fault handler for 64-bit builds since
kvm_tdp_mmu_map() does not exist in 32-bit builds.

No functional change intended.

Signed-off-by: David Matlack <dmatlack@google.com>
Reviewed-by: Isaku Yamahata <isaku.yamahata@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20220921173546.2674386-9-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-27 06:03:00 -05:00
David Matlack
2d75ce0300 KVM: x86/mmu: Initialize fault.{gfn,slot} earlier for direct MMUs
Move the initialization of fault.{gfn,slot} earlier in the page fault
handling code for fully direct MMUs. This will enable a future commit to
split out TDP MMU page fault handling without needing to duplicate the
initialization of these 2 fields.

Opportunistically take advantage of the fact that fault.gfn is
initialized in kvm_tdp_page_fault() rather than recomputing it from
fault->addr.

No functional change intended.

Signed-off-by: David Matlack <dmatlack@google.com>
Reviewed-by: Isaku Yamahata <isaku.yamahata@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20220921173546.2674386-8-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-27 06:02:59 -05:00
David Matlack
f09948ec1f KVM: x86/mmu: Handle no-slot faults in kvm_faultin_pfn()
Handle faults on GFNs that do not have a backing memslot in
kvm_faultin_pfn() and drop handle_abnormal_pfn(). This eliminates
duplicate code in the various page fault handlers.

Opportunistically tweak the comment about handling gfn > host.MAXPHYADDR
to reflect that the effect of returning RET_PF_EMULATE at that point is
to avoid creating an MMIO SPTE for such GFNs.

No functional change intended.

Signed-off-by: David Matlack <dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20220921173546.2674386-7-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-27 06:02:59 -05:00
David Matlack
897e4526e5 KVM: x86/mmu: Avoid memslot lookup during KVM_PFN_ERR_HWPOISON handling
Pass the kvm_page_fault struct down to kvm_handle_error_pfn() to avoid a
memslot lookup when handling KVM_PFN_ERR_HWPOISON. Opportunistically
move the gfn_to_hva_memslot() call and @current down into
kvm_send_hwpoison_signal() to cut down on line lengths.

No functional change intended.

Signed-off-by: David Matlack <dmatlack@google.com>
Reviewed-by: Isaku Yamahata <isaku.yamahata@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20220921173546.2674386-6-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-27 06:02:59 -05:00
David Matlack
7bd9645348 KVM: x86/mmu: Handle error PFNs in kvm_faultin_pfn()
Handle error PFNs in kvm_faultin_pfn() rather than relying on the caller
to invoke handle_abnormal_pfn() after kvm_faultin_pfn().
Opportunistically rename kvm_handle_bad_page() to kvm_handle_error_pfn()
to make it more consistent with is_error_pfn().

This commit moves KVM closer to being able to drop
handle_abnormal_pfn(), which will reduce the amount of duplicate code in
the various page fault handlers.

No functional change intended.

Signed-off-by: David Matlack <dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20220921173546.2674386-5-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-27 06:02:58 -05:00
David Matlack
90c54c19f8 KVM: x86/mmu: Grab mmu_invalidate_seq in kvm_faultin_pfn()
Grab mmu_invalidate_seq in kvm_faultin_pfn() and stash it in struct
kvm_page_fault. The eliminates duplicate code and reduces the amount of
parameters needed for is_page_fault_stale().

Preemptively split out __kvm_faultin_pfn() to a separate function for
use in subsequent commits.

No functional change intended.

Signed-off-by: David Matlack <dmatlack@google.com>
Reviewed-by: Isaku Yamahata <isaku.yamahata@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20220921173546.2674386-4-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-27 06:02:58 -05:00
David Matlack
991c8047b7 KVM: x86/mmu: Move TDP MMU VM init/uninit behind tdp_mmu_enabled
Move kvm_mmu_{init,uninit}_tdp_mmu() behind tdp_mmu_enabled. This makes
these functions consistent with the rest of the calls into the TDP MMU
from mmu.c, and which is now possible since tdp_mmu_enabled is only
modified when the x86 vendor module is loaded. i.e. It will never change
during the lifetime of a VM.

This change also enabled removing the stub definitions for 32-bit KVM,
as the compiler will just optimize the calls out like it does for all
the other TDP MMU functions.

No functional change intended.

Signed-off-by: David Matlack <dmatlack@google.com>
Reviewed-by: Isaku Yamahata <isaku.yamahata@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20220921173546.2674386-3-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-27 06:02:57 -05:00
David Matlack
3af15ff47c KVM: x86/mmu: Change tdp_mmu to a read-only parameter
Change tdp_mmu to a read-only parameter and drop the per-vm
tdp_mmu_enabled. For 32-bit KVM, make tdp_mmu_enabled a macro that is
always false so that the compiler can continue omitting cals to the TDP
MMU.

The TDP MMU was introduced in 5.10 and has been enabled by default since
5.15. At this point there are no known functionality gaps between the
TDP MMU and the shadow MMU, and the TDP MMU uses less memory and scales
better with the number of vCPUs. In other words, there is no good reason
to disable the TDP MMU on a live system.

Purposely do not drop tdp_mmu=N support (i.e. do not force 64-bit KVM to
always use the TDP MMU) since tdp_mmu=N is still used to get test
coverage of KVM's shadow MMU TDP support, which is used in 32-bit KVM.

Signed-off-by: David Matlack <dmatlack@google.com>
Reviewed-by: Kai Huang <kai.huang@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20220921173546.2674386-2-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-27 06:02:57 -05:00
Lai Jiangshan
641e680858 kvm: x86/mmu: Warn on linking when sp->unsync_children
Since the commit 65855ed8b034 ("KVM: X86: Synchronize the shadow
pagetable before link it"), no sp would be linked with
sp->unsync_children = 1.

So make it WARN if it is the case.

Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com>
Message-Id: <20221212090106.378206-1-jiangshanlai@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-27 06:02:56 -05:00
Vitaly Kuznetsov
1567037614 KVM: VMX: Resurrect vmcs_conf sanitization for KVM-on-Hyper-V
Commit 9bcb90650e31 ("KVM: VMX: Get rid of eVMCS specific VMX controls
sanitization") dropped 'vmcs_conf' sanitization for KVM-on-Hyper-V because
there's no known Hyper-V version which would expose a feature
unsupported in eVMCS in VMX feature MSRs. This works well for all
currently existing Hyper-V version, however, future Hyper-V versions
may add features which are supported by KVM and are currently missing
in eVMCSv1 definition (e.g. APIC virtualization, PML,...). When this
happens, existing KVMs will get broken. With the inverted 'unsupported
by eVMCSv1' checks, we can resurrect vmcs_conf sanitization and make
KVM future proof.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20221104144708.435865-5-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-27 06:02:56 -05:00
Vitaly Kuznetsov
746b183391 KVM: nVMX: Prepare to sanitize tertiary execution controls with eVMCS
In preparation to restoring vmcs_conf sanitization for KVM-on-Hyper-V,
(and for completeness) add tertiary VM-execution controls to
'evmcs_supported_ctrls'.

No functional change intended as KVM doesn't yet expose
MSR_IA32_VMX_PROCBASED_CTLS3 to its guests.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20221104144708.435865-4-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-27 06:02:55 -05:00
Vitaly Kuznetsov
70b31e50fb KVM: nVMX: Invert 'unsupported by eVMCSv1' check
When a new feature gets implemented in KVM, EVMCS1_UNSUPPORTED_* defines
need to be adjusted to avoid the situation when the feature is exposed
to the guest but there's no corresponding eVMCS field[s] for it. This
is not obvious and fragile. Invert 'unsupported by eVMCSv1' check and
make it 'supported by eVMCSv1' instead, this way it's much harder to
make a mistake. New features will get added to EVMCS1_SUPPORTED_*
defines when the corresponding fields are added to eVMCS definition.

No functional change intended. EVMCS1_SUPPORTED_* defines are composed
by taking KVM_{REQUIRED,OPTIONAL}_VMX_ defines and filtering out what
was previously known as EVMCS1_UNSUPPORTED_*.

From all the controls, SECONDARY_EXEC_TSC_SCALING requires special
handling as it's actually present in eVMCSv1 definition but is not
currently supported for Hyper-V-on-KVM, just for KVM-on-Hyper-V. As
evmcs_supported_ctrls will be used for both scenarios, just add it
there instead of EVMCS1_SUPPORTED_2NDEXEC.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20221104144708.435865-3-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-27 06:02:55 -05:00
Vitaly Kuznetsov
bbbaf8cd17 KVM: nVMX: Sanitize primary processor-based VM-execution controls with eVMCS too
The only unsupported primary processor-based VM-execution control at the
moment is CPU_BASED_ACTIVATE_TERTIARY_CONTROLS and KVM doesn't expose it
in nested VMX feature MSRs anyway (see nested_vmx_setup_ctls_msrs())
but in preparation to inverting "unsupported with eVMCS" checks (and
for completeness) it's better to sanitize MSR_IA32_VMX_PROCBASED_CTLS/
MSR_IA32_VMX_TRUE_PROCBASED_CTLS too.

No functional change intended.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20221104144708.435865-2-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-27 06:02:54 -05:00
David Woodhouse
b0305c1e0e KVM: x86/xen: Add KVM_XEN_INVALID_GPA and KVM_XEN_INVALID_GFN to uapi
These are (uint64_t)-1 magic values are a userspace ABI, allowing the
shared info pages and other enlightenments to be disabled. This isn't
a Xen ABI because Xen doesn't let the guest turn these off except with
the full SHUTDOWN_soft_reset mechanism. Under KVM, the userspace VMM is
expected to handle soft reset, and tear down the kernel parts of the
enlightenments accordingly.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Message-Id: <20221226120320.1125390-5-dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-27 06:01:49 -05:00
Michal Luczaj
1c14faa508 KVM: x86/xen: Simplify eventfd IOCTLs
Port number is validated in kvm_xen_setattr_evtchn().
Remove superfluous checks in kvm_xen_eventfd_assign() and
kvm_xen_eventfd_update().

Signed-off-by: Michal Luczaj <mhal@rbox.co>
Message-Id: <20221222203021.1944101-3-mhal@rbox.co>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Message-Id: <20221226120320.1125390-4-dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-27 06:01:49 -05:00
Paolo Bonzini
70eae03087 KVM: x86/xen: Fix SRCU/RCU usage in readers of evtchn_ports
The evtchnfd structure itself must be protected by either kvm->lock or
SRCU. Use the former in kvm_xen_eventfd_update(), since the lock is
being taken anyway; kvm_xen_hcall_evtchn_send() instead is a reader and
does not need kvm->lock, and is called in SRCU critical section from the
kvm_x86_handle_exit function.

It is also important to use rcu_read_{lock,unlock}() in
kvm_xen_hcall_evtchn_send(), because idr_remove() will *not*
use synchronize_srcu() to wait for readers to complete.

Remove a superfluous if (kvm) check before calling synchronize_srcu()
in kvm_xen_eventfd_deassign() where kvm has been dereferenced already.

Co-developed-by: Michal Luczaj <mhal@rbox.co>
Signed-off-by: Michal Luczaj <mhal@rbox.co>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Message-Id: <20221226120320.1125390-3-dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-27 06:01:49 -05:00
David Woodhouse
92c58965e9 KVM: x86/xen: Use kvm_read_guest_virt() instead of open-coding it badly
In particular, we shouldn't assume that being contiguous in guest virtual
address space means being contiguous in guest *physical* address space.

In dropping the manual calls to kvm_mmu_gva_to_gpa_system(), also drop
the srcu_read_lock() that was around them. All call sites are reached
from kvm_xen_hypercall() which is called from the handle_exit function
with the read lock already held.

       536395260 ("KVM: x86/xen: handle PV timers oneshot mode")
       1a65105a5 ("KVM: x86/xen: handle PV spinlocks slowpath")

Fixes: 2fd6df2f2 ("KVM: x86/xen: intercept EVTCHNOP_send from guests")
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Message-Id: <20221226120320.1125390-2-dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-27 06:01:48 -05:00
Michal Luczaj
385407a69d KVM: x86/xen: Fix memory leak in kvm_xen_write_hypercall_page()
Release page irrespectively of kvm_vcpu_write_guest() return value.

Suggested-by: Paul Durrant <paul@xen.org>
Fixes: 23200b7a30de ("KVM: x86/xen: intercept xen hypercalls if enabled")
Signed-off-by: Michal Luczaj <mhal@rbox.co>
Message-Id: <20221220151454.712165-1-mhal@rbox.co>
Reviewed-by: Paul Durrant <paul@xen.org>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Message-Id: <20221226120320.1125390-1-dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-27 06:01:48 -05:00
Lai Jiangshan
562f5bc48a kvm: x86/mmu: Remove duplicated "be split" in spte.h
"be split be split" -> "be split"

Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com>
Message-Id: <20221207120505.9175-1-jiangshanlai@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-27 06:00:51 -05:00
Sean Christopherson
50a9ac2598 KVM: x86/mmu: Don't install TDP MMU SPTE if SP has unexpected level
Don't install a leaf TDP MMU SPTE if the parent page's level doesn't
match the target level of the fault, and instead have the vCPU retry the
faulting instruction after warning.  Continuing on is completely
unnecessary as the absolute worst case scenario of retrying is DoSing
the vCPU, whereas continuing on all but guarantees bigger explosions, e.g.

  ------------[ cut here ]------------
  kernel BUG at arch/x86/kvm/mmu/tdp_mmu.c:559!
  invalid opcode: 0000 [#1] SMP
  CPU: 1 PID: 1025 Comm: nx_huge_pages_t Tainted: G        W          6.1.0-rc4+ #64
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
  RIP: 0010:__handle_changed_spte.cold+0x95/0x9c
  RSP: 0018:ffffc9000072faf8 EFLAGS: 00010246
  RAX: 00000000000000c1 RBX: ffffc90000731000 RCX: 0000000000000027
  RDX: 0000000000000000 RSI: 00000000ffffdfff RDI: ffff888277c5b4c8
  RBP: 0600000112400bf3 R08: ffff888277c5b4c0 R09: ffffc9000072f9a0
  R10: 0000000000000001 R11: 0000000000000001 R12: 06000001126009f3
  R13: 0000000000000002 R14: 0000000012600901 R15: 0000000012400b01
  FS:  00007fba9f853740(0000) GS:ffff888277c40000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 0000000000000000 CR3: 000000010aa7a003 CR4: 0000000000172ea0
  Call Trace:
   <TASK>
   kvm_tdp_mmu_map+0x3b0/0x510
   kvm_tdp_page_fault+0x10c/0x130
   kvm_mmu_page_fault+0x103/0x680
   vmx_handle_exit+0x132/0x5a0 [kvm_intel]
   vcpu_enter_guest+0x60c/0x16f0
   kvm_arch_vcpu_ioctl_run+0x1e2/0x9d0
   kvm_vcpu_ioctl+0x271/0x660
   __x64_sys_ioctl+0x80/0xb0
   do_syscall_64+0x2b/0x50
   entry_SYSCALL_64_after_hwframe+0x46/0xb0
   </TASK>
  Modules linked in: kvm_intel
  ---[ end trace 0000000000000000 ]---

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221213033030.83345-5-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-23 12:33:53 -05:00
Sean Christopherson
21a36ac6b6 KVM: x86/mmu: Re-check under lock that TDP MMU SP hugepage is disallowed
Re-check sp->nx_huge_page_disallowed under the tdp_mmu_pages_lock spinlock
when adding a new shadow page in the TDP MMU.  To ensure the NX reclaim
kthread can't see a not-yet-linked shadow page, the page fault path links
the new page table prior to adding the page to possible_nx_huge_pages.

If the page is zapped by different task, e.g. because dirty logging is
disabled, between linking the page and adding it to the list, KVM can end
up triggering use-after-free by adding the zapped SP to the aforementioned
list, as the zapped SP's memory is scheduled for removal via RCU callback.
The bug is detected by the sanity checks guarded by CONFIG_DEBUG_LIST=y,
i.e. the below splat is just one possible signature.

  ------------[ cut here ]------------
  list_add corruption. prev->next should be next (ffffc9000071fa70), but was ffff88811125ee38. (prev=ffff88811125ee38).
  WARNING: CPU: 1 PID: 953 at lib/list_debug.c:30 __list_add_valid+0x79/0xa0
  Modules linked in: kvm_intel
  CPU: 1 PID: 953 Comm: nx_huge_pages_t Tainted: G        W          6.1.0-rc4+ #71
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
  RIP: 0010:__list_add_valid+0x79/0xa0
  RSP: 0018:ffffc900006efb68 EFLAGS: 00010286
  RAX: 0000000000000000 RBX: ffff888116cae8a0 RCX: 0000000000000027
  RDX: 0000000000000027 RSI: 0000000100001872 RDI: ffff888277c5b4c8
  RBP: ffffc90000717000 R08: ffff888277c5b4c0 R09: ffffc900006efa08
  R10: 0000000000199998 R11: 0000000000199a20 R12: ffff888116cae930
  R13: ffff88811125ee38 R14: ffffc9000071fa70 R15: ffff88810b794f90
  FS:  00007fc0415d2740(0000) GS:ffff888277c40000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 0000000000000000 CR3: 0000000115201006 CR4: 0000000000172ea0
  Call Trace:
   <TASK>
   track_possible_nx_huge_page+0x53/0x80
   kvm_tdp_mmu_map+0x242/0x2c0
   kvm_tdp_page_fault+0x10c/0x130
   kvm_mmu_page_fault+0x103/0x680
   vmx_handle_exit+0x132/0x5a0 [kvm_intel]
   vcpu_enter_guest+0x60c/0x16f0
   kvm_arch_vcpu_ioctl_run+0x1e2/0x9d0
   kvm_vcpu_ioctl+0x271/0x660
   __x64_sys_ioctl+0x80/0xb0
   do_syscall_64+0x2b/0x50
   entry_SYSCALL_64_after_hwframe+0x46/0xb0
   </TASK>
  ---[ end trace 0000000000000000 ]---

Fixes: 61f94478547b ("KVM: x86/mmu: Set disallowed_nx_huge_page in TDP MMU before setting SPTE")
Reported-by: Greg Thelen <gthelen@google.com>
Analyzed-by: David Matlack <dmatlack@google.com>
Cc: David Matlack <dmatlack@google.com>
Cc: Ben Gardon <bgardon@google.com>
Cc: Mingwei Zhang <mizhang@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221213033030.83345-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-23 12:33:53 -05:00
Sean Christopherson
80a3e4ae96 KVM: x86/mmu: Map TDP MMU leaf SPTE iff target level is reached
Map the leaf SPTE when handling a TDP MMU page fault if and only if the
target level is reached.  A recent commit reworked the retry logic and
incorrectly assumed that walking SPTEs would never "fail", as the loop
either bails (retries) or installs parent SPs.  However, the iterator
itself will bail early if it detects a frozen (REMOVED) SPTE when
stepping down.   The TDP iterator also rereads the current SPTE before
stepping down specifically to avoid walking into a part of the tree that
is being removed, which means it's possible to terminate the loop without
the guts of the loop observing the frozen SPTE, e.g. if a different task
zaps a parent SPTE between the initial read and try_step_down()'s refresh.

Mapping a leaf SPTE at the wrong level results in all kinds of badness as
page table walkers interpret the SPTE as a page table, not a leaf, and
walk into the weeds.

  ------------[ cut here ]------------
  WARNING: CPU: 1 PID: 1025 at arch/x86/kvm/mmu/tdp_mmu.c:1070 kvm_tdp_mmu_map+0x481/0x510
  Modules linked in: kvm_intel
  CPU: 1 PID: 1025 Comm: nx_huge_pages_t Tainted: G        W          6.1.0-rc4+ #64
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
  RIP: 0010:kvm_tdp_mmu_map+0x481/0x510
  RSP: 0018:ffffc9000072fba8 EFLAGS: 00010286
  RAX: 0000000000000000 RBX: ffffc9000072fcc0 RCX: 0000000000000027
  RDX: 0000000000000027 RSI: 00000000ffffdfff RDI: ffff888277c5b4c8
  RBP: ffff888107d45a10 R08: ffff888277c5b4c0 R09: ffffc9000072fa48
  R10: 0000000000000001 R11: 0000000000000001 R12: ffffc9000073a0e0
  R13: ffff88810fc54800 R14: ffff888107d1ae60 R15: ffff88810fc54f90
  FS:  00007fba9f853740(0000) GS:ffff888277c40000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 0000000000000000 CR3: 000000010aa7a003 CR4: 0000000000172ea0
  Call Trace:
   <TASK>
   kvm_tdp_page_fault+0x10c/0x130
   kvm_mmu_page_fault+0x103/0x680
   vmx_handle_exit+0x132/0x5a0 [kvm_intel]
   vcpu_enter_guest+0x60c/0x16f0
   kvm_arch_vcpu_ioctl_run+0x1e2/0x9d0
   kvm_vcpu_ioctl+0x271/0x660
   __x64_sys_ioctl+0x80/0xb0
   do_syscall_64+0x2b/0x50
   entry_SYSCALL_64_after_hwframe+0x46/0xb0
   </TASK>
  ---[ end trace 0000000000000000 ]---
  Invalid SPTE change: cannot replace a present leaf
  SPTE with another present leaf SPTE mapping a
  different PFN!
  as_id: 0 gfn: 100200 old_spte: 600000112400bf3 new_spte: 6000001126009f3 level: 2
  ------------[ cut here ]------------
  kernel BUG at arch/x86/kvm/mmu/tdp_mmu.c:559!
  invalid opcode: 0000 [#1] SMP
  CPU: 1 PID: 1025 Comm: nx_huge_pages_t Tainted: G        W          6.1.0-rc4+ #64
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
  RIP: 0010:__handle_changed_spte.cold+0x95/0x9c
  RSP: 0018:ffffc9000072faf8 EFLAGS: 00010246
  RAX: 00000000000000c1 RBX: ffffc90000731000 RCX: 0000000000000027
  RDX: 0000000000000000 RSI: 00000000ffffdfff RDI: ffff888277c5b4c8
  RBP: 0600000112400bf3 R08: ffff888277c5b4c0 R09: ffffc9000072f9a0
  R10: 0000000000000001 R11: 0000000000000001 R12: 06000001126009f3
  R13: 0000000000000002 R14: 0000000012600901 R15: 0000000012400b01
  FS:  00007fba9f853740(0000) GS:ffff888277c40000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 0000000000000000 CR3: 000000010aa7a003 CR4: 0000000000172ea0
  Call Trace:
   <TASK>
   kvm_tdp_mmu_map+0x3b0/0x510
   kvm_tdp_page_fault+0x10c/0x130
   kvm_mmu_page_fault+0x103/0x680
   vmx_handle_exit+0x132/0x5a0 [kvm_intel]
   vcpu_enter_guest+0x60c/0x16f0
   kvm_arch_vcpu_ioctl_run+0x1e2/0x9d0
   kvm_vcpu_ioctl+0x271/0x660
   __x64_sys_ioctl+0x80/0xb0
   do_syscall_64+0x2b/0x50
   entry_SYSCALL_64_after_hwframe+0x46/0xb0
   </TASK>
  Modules linked in: kvm_intel
  ---[ end trace 0000000000000000 ]---

Fixes: 63d28a25e04c ("KVM: x86/mmu: simplify kvm_tdp_mmu_map flow when guest has to retry")
Cc: Robert Hoo <robert.hu@linux.intel.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221213033030.83345-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-23 12:33:52 -05:00
Sean Christopherson
f5d16bb9be KVM: x86/mmu: Don't attempt to map leaf if target TDP MMU SPTE is frozen
Hoist the is_removed_spte() check above the "level == goal_level" check
when walking SPTEs during a TDP MMU page fault to avoid attempting to map
a leaf entry if said entry is frozen by a different task/vCPU.

  ------------[ cut here ]------------
  WARNING: CPU: 3 PID: 939 at arch/x86/kvm/mmu/tdp_mmu.c:653 kvm_tdp_mmu_map+0x269/0x4b0
  Modules linked in: kvm_intel
  CPU: 3 PID: 939 Comm: nx_huge_pages_t Not tainted 6.1.0-rc4+ #67
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
  RIP: 0010:kvm_tdp_mmu_map+0x269/0x4b0
  RSP: 0018:ffffc9000068fba8 EFLAGS: 00010246
  RAX: 00000000000005a0 RBX: ffffc9000068fcc0 RCX: 0000000000000005
  RDX: ffff88810741f000 RSI: ffff888107f04600 RDI: ffffc900006a3000
  RBP: 060000010b000bf3 R08: 0000000000000000 R09: 0000000000000000
  R10: 0000000000000000 R11: 000ffffffffff000 R12: 0000000000000005
  R13: ffff888113670000 R14: ffff888107464958 R15: 0000000000000000
  FS:  00007f01c942c740(0000) GS:ffff888277cc0000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 0000000000000000 CR3: 0000000117013006 CR4: 0000000000172ea0
  Call Trace:
   <TASK>
   kvm_tdp_page_fault+0x10c/0x130
   kvm_mmu_page_fault+0x103/0x680
   vmx_handle_exit+0x132/0x5a0 [kvm_intel]
   vcpu_enter_guest+0x60c/0x16f0
   kvm_arch_vcpu_ioctl_run+0x1e2/0x9d0
   kvm_vcpu_ioctl+0x271/0x660
   __x64_sys_ioctl+0x80/0xb0
   do_syscall_64+0x2b/0x50
   entry_SYSCALL_64_after_hwframe+0x46/0xb0
   </TASK>
  ---[ end trace 0000000000000000 ]---

Fixes: 63d28a25e04c ("KVM: x86/mmu: simplify kvm_tdp_mmu_map flow when guest has to retry")
Cc: Robert Hoo <robert.hu@linux.intel.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Robert Hoo <robert.hu@linux.intel.com>
Message-Id: <20221213033030.83345-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-23 12:33:52 -05:00
Sean Christopherson
a0860d68a2 KVM: nVMX: Don't stuff secondary execution control if it's not supported
When stuffing the allowed secondary execution controls for nested VMX in
response to CPUID updates, don't set the allowed-1 bit for a feature that
isn't supported by KVM, i.e. isn't allowed by the canonical vmcs_config.

WARN if KVM attempts to manipulate a feature that isn't supported.  All
features that are currently stuffed are always advertised to L1 for
nested VMX if they are supported in KVM's base configuration, and no
additional features should ever be added to the CPUID-induced stuffing
(updating VMX MSRs in response to CPUID updates is a long-standing KVM
flaw that is slowly being fixed).

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221213062306.667649-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-23 12:32:03 -05:00
Sean Christopherson
31de69f4ee KVM: nVMX: Properly expose ENABLE_USR_WAIT_PAUSE control to L1
Set ENABLE_USR_WAIT_PAUSE in KVM's supported VMX MSR configuration if the
feature is supported in hardware and enabled in KVM's base, non-nested
configuration, i.e. expose ENABLE_USR_WAIT_PAUSE to L1 if it's supported.
This fixes a bug where saving/restoring, i.e. migrating, a vCPU will fail
if WAITPKG (the associated CPUID feature) is enabled for the vCPU, and
obviously allows L1 to enable the feature for L2.

KVM already effectively exposes ENABLE_USR_WAIT_PAUSE to L1 by stuffing
the allowed-1 control ina vCPU's virtual MSR_IA32_VMX_PROCBASED_CTLS2 when
updating secondary controls in response to KVM_SET_CPUID(2), but (a) that
depends on flawed code (KVM shouldn't touch VMX MSRs in response to CPUID
updates) and (b) runs afoul of vmx_restore_control_msr()'s restriction
that the guest value must be a strict subset of the supported host value.

Although no past commit explicitly enabled nested support for WAITPKG,
doing so is safe and functionally correct from an architectural
perspective as no additional KVM support is needed to virtualize TPAUSE,
UMONITOR, and UMWAIT for L2 relative to L1, and KVM already forwards
VM-Exits to L1 as necessary (commit bf653b78f960, "KVM: vmx: Introduce
handle_unexpected_vmexit and handle WAITPKG vmexit").

Note, KVM always keeps the hosts MSR_IA32_UMWAIT_CONTROL resident in
hardware, i.e. always runs both L1 and L2 with the host's power management
settings for TPAUSE and UMWAIT.  See commit bf09fb6cba4f ("KVM: VMX: Stop
context switching MSR_IA32_UMWAIT_CONTROL") for more details.

Fixes: e69e72faa3a0 ("KVM: x86: Add support for user wait instructions")
Cc: stable@vger.kernel.org
Reported-by: Aaron Lewis <aaronlewis@google.com>
Reported-by: Yu Zhang <yu.c.zhang@linux.intel.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Message-Id: <20221213062306.667649-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-23 12:22:37 -05:00
Sean Christopherson
057b18756b KVM: nVMX: Document that ignoring memory failures for VMCLEAR is deliberate
Explicitly drop the result of kvm_vcpu_write_guest() when writing the
"launch state" as part of VMCLEAR emulation, and add a comment to call
out that KVM's behavior is architecturally valid.  Intel's pseudocode
effectively says that VMCLEAR is a nop if the target VMCS address isn't
in memory, e.g. if the address points at MMIO.

Add a FIXME to call out that suppressing failures on __copy_to_user() is
wrong, as memory (a memslot) does exist in that case.  Punt the issue to
the future as open coding kvm_vcpu_write_guest() just to make sure the
guest dies with -EFAULT isn't worth the extra complexity.  The flaw will
need to be addressed if KVM ever does something intelligent on uaccess
failures, e.g. to support post-copy demand paging, but in that case KVM
will need a more thorough overhaul, i.e. VMCLEAR shouldn't need to open
code a core KVM helper.

No functional change intended.

Reported-by: coverity-bot <keescook+coverity-bot@chromium.org>
Addresses-Coverity-ID: 1527765 ("Error handling issues")
Fixes: 587d7e72aedc ("kvm: nVMX: VMCLEAR should not cause the vCPU to shut down")
Cc: Jim Mattson <jmattson@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221220154224.526568-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-23 12:16:49 -05:00
Sean Christopherson
77b1908e10 KVM: x86: Sanity check inputs to kvm_handle_memory_failure()
Add a sanity check in kvm_handle_memory_failure() to assert that a valid
x86_exception structure is provided if the memory "failure" wants to
propagate a fault into the guest.  If a memory failure happens during a
direct guest physical memory access, e.g. for nested VMX, KVM hardcodes
the failure to X86EMUL_IO_NEEDED and doesn't provide an exception pointer
(because the exception struct would just be filled with garbage).

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221220153427.514032-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-23 12:15:25 -05:00
Peng Hao
3c649918b7 KVM: x86: Simplify kvm_apic_hw_enabled
kvm_apic_hw_enabled() only needs to return bool, there is no place
to use the return value of MSR_IA32_APICBASE_ENABLE.

Signed-off-by: Peng Hao <flyingpeng@tencent.com>
Message-Id: <CAPm50aJ=BLXNWT11+j36Dd6d7nz2JmOBk4u7o_NPQ0N61ODu1g@mail.gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-23 12:09:28 -05:00
Vitaly Kuznetsov
8b9e13d2de KVM: x86: hyper-v: Fix 'using uninitialized value' Coverity warning
In kvm_hv_flush_tlb(), 'data_offset' and 'consumed_xmm_halves' variables
are used in a mutually exclusive way: in 'hc->fast' we count in 'XMM
halves' and increase 'data_offset' otherwise. Coverity discovered, that in
one case both variables are incremented unconditionally. This doesn't seem
to cause any issues as the only user of 'data_offset'/'consumed_xmm_halves'
data is kvm_hv_get_tlb_flush_entries() -> kvm_hv_get_hc_data() which also
takes into account 'hc->fast' but is still worth fixing.

To make things explicit, put 'data_offset' and 'consumed_xmm_halves' to
'struct kvm_hv_hcall' as a union and use at call sites. This allows to
remove explicit 'data_offset'/'consumed_xmm_halves' parameters from
kvm_hv_get_hc_data()/kvm_get_sparse_vp_set()/kvm_hv_get_tlb_flush_entries()
helpers.

Note: 'struct kvm_hv_hcall' is allocated on stack in kvm_hv_hypercall() and
is not zeroed, consumers are supposed to initialize the appropriate field
if needed.

Reported-by: coverity-bot <keescook+coverity-bot@chromium.org>
Addresses-Coverity-ID: 1527764 ("Uninitialized variables")
Fixes: 260970862c88 ("KVM: x86: hyper-v: Handle HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST{,EX} calls gently")
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221208102700.959630-1-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-23 12:08:16 -05:00
Adamos Ttofari
fceb3a36c2 KVM: x86: ioapic: Fix level-triggered EOI and userspace I/OAPIC reconfigure race
When scanning userspace I/OAPIC entries, intercept EOI for level-triggered
IRQs if the current vCPU has a pending and/or in-service IRQ for the
vector in its local API, even if the vCPU doesn't match the new entry's
destination.  This fixes a race between userspace I/OAPIC reconfiguration
and IRQ delivery that results in the vector's bit being left set in the
remote IRR due to the eventual EOI not being forwarded to the userspace
I/OAPIC.

Commit 0fc5a36dd6b3 ("KVM: x86: ioapic: Fix level-triggered EOI and IOAPIC
reconfigure race") fixed the in-kernel IOAPIC, but not the userspace
IOAPIC configuration, which has a similar race.

Fixes: 0fc5a36dd6b3 ("KVM: x86: ioapic: Fix level-triggered EOI and IOAPIC reconfigure race")

Signed-off-by: Adamos Ttofari <attofari@amazon.de>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221208094415.12723-1-attofari@amazon.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-23 12:07:40 -05:00
Like Xu
55c590adfe KVM: x86/pmu: Prevent zero period event from being repeatedly released
The current vPMU can reuse the same pmc->perf_event for the same
hardware event via pmc_pause/resume_counter(), but this optimization
does not apply to a portion of the TSX events (e.g., "event=0x3c,in_tx=1,
in_tx_cp=1"), where event->attr.sample_period is legally zero at creation,
thus making the perf call to perf_event_period() meaningless (no need to
adjust sample period in this case), and instead causing such reusable
perf_events to be repeatedly released and created.

Avoid releasing zero sample_period events by checking is_sampling_event()
to follow the previously enable/disable optimization.

Signed-off-by: Like Xu <likexu@tencent.com>
Message-Id: <20221207071506.15733-2-likexu@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-23 12:06:45 -05:00
Paolo Bonzini
9352e7470a Merge remote-tracking branch 'kvm/queue' into HEAD
x86 Xen-for-KVM:

* Allow the Xen runstate information to cross a page boundary

* Allow XEN_RUNSTATE_UPDATE flag behaviour to be configured

* add support for 32-bit guests in SCHEDOP_poll

x86 fixes:

* One-off fixes for various emulation flows (SGX, VMXON, NRIPS=0).

* Reinstate IBPB on emulated VM-Exit that was incorrectly dropped a few
   years back when eliminating unnecessary barriers when switching between
   vmcs01 and vmcs02.

* Clean up the MSR filter docs.

* Clean up vmread_error_trampoline() to make it more obvious that params
  must be passed on the stack, even for x86-64.

* Let userspace set all supported bits in MSR_IA32_FEAT_CTL irrespective
  of the current guest CPUID.

* Fudge around a race with TSC refinement that results in KVM incorrectly
  thinking a guest needs TSC scaling when running on a CPU with a
  constant TSC, but no hardware-enumerated TSC frequency.

* Advertise (on AMD) that the SMM_CTL MSR is not supported

* Remove unnecessary exports

Selftests:

* Fix an inverted check in the access tracking perf test, and restore
  support for asserting that there aren't too many idle pages when
  running on bare metal.

* Fix an ordering issue in the AMX test introduced by recent conversions
  to use kvm_cpu_has(), and harden the code to guard against similar bugs
  in the future.  Anything that tiggers caching of KVM's supported CPUID,
  kvm_cpu_has() in this case, effectively hides opt-in XSAVE features if
  the caching occurs before the test opts in via prctl().

* Fix build errors that occur in certain setups (unsure exactly what is
  unique about the problematic setup) due to glibc overriding
  static_assert() to a variant that requires a custom message.

* Introduce actual atomics for clear/set_bit() in selftests

Documentation:

* Remove deleted ioctls from documentation

* Various fixes
2022-12-12 15:54:07 -05:00
Paolo Bonzini
eb5618911a KVM/arm64 updates for 6.2
- Enable the per-vcpu dirty-ring tracking mechanism, together with an
   option to keep the good old dirty log around for pages that are
   dirtied by something other than a vcpu.
 
 - Switch to the relaxed parallel fault handling, using RCU to delay
   page table reclaim and giving better performance under load.
 
 - Relax the MTE ABI, allowing a VMM to use the MAP_SHARED mapping
   option, which multi-process VMMs such as crosvm rely on.
 
 - Merge the pKVM shadow vcpu state tracking that allows the hypervisor
   to have its own view of a vcpu, keeping that state private.
 
 - Add support for the PMUv3p5 architecture revision, bringing support
   for 64bit counters on systems that support it, and fix the
   no-quite-compliant CHAIN-ed counter support for the machines that
   actually exist out there.
 
 - Fix a handful of minor issues around 52bit VA/PA support (64kB pages
   only) as a prefix of the oncoming support for 4kB and 16kB pages.
 
 - Add/Enable/Fix a bunch of selftests covering memslots, breakpoints,
   stage-2 faults and access tracking. You name it, we got it, we
   probably broke it.
 
 - Pick a small set of documentation and spelling fixes, because no
   good merge window would be complete without those.
 
 As a side effect, this tag also drags:
 
 - The 'kvmarm-fixes-6.1-3' tag as a dependency to the dirty-ring
   series
 
 - A shared branch with the arm64 tree that repaints all the system
   registers to match the ARM ARM's naming, and resulting in
   interesting conflicts
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Merge tag 'kvmarm-6.2' of https://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm64 updates for 6.2

- Enable the per-vcpu dirty-ring tracking mechanism, together with an
  option to keep the good old dirty log around for pages that are
  dirtied by something other than a vcpu.

- Switch to the relaxed parallel fault handling, using RCU to delay
  page table reclaim and giving better performance under load.

- Relax the MTE ABI, allowing a VMM to use the MAP_SHARED mapping
  option, which multi-process VMMs such as crosvm rely on.

- Merge the pKVM shadow vcpu state tracking that allows the hypervisor
  to have its own view of a vcpu, keeping that state private.

- Add support for the PMUv3p5 architecture revision, bringing support
  for 64bit counters on systems that support it, and fix the
  no-quite-compliant CHAIN-ed counter support for the machines that
  actually exist out there.

- Fix a handful of minor issues around 52bit VA/PA support (64kB pages
  only) as a prefix of the oncoming support for 4kB and 16kB pages.

- Add/Enable/Fix a bunch of selftests covering memslots, breakpoints,
  stage-2 faults and access tracking. You name it, we got it, we
  probably broke it.

- Pick a small set of documentation and spelling fixes, because no
  good merge window would be complete without those.

As a side effect, this tag also drags:

- The 'kvmarm-fixes-6.1-3' tag as a dependency to the dirty-ring
  series

- A shared branch with the arm64 tree that repaints all the system
  registers to match the ARM ARM's naming, and resulting in
  interesting conflicts
2022-12-09 09:12:12 +01:00
Marc Zyngier
a937f37d85 Merge branch kvm-arm64/dirty-ring into kvmarm-master/next
* kvm-arm64/dirty-ring:
  : .
  : Add support for the "per-vcpu dirty-ring tracking with a bitmap
  : and sprinkles on top", courtesy of Gavin Shan.
  :
  : This branch drags the kvmarm-fixes-6.1-3 tag which was already
  : merged in 6.1-rc4 so that the branch is in a working state.
  : .
  KVM: Push dirty information unconditionally to backup bitmap
  KVM: selftests: Automate choosing dirty ring size in dirty_log_test
  KVM: selftests: Clear dirty ring states between two modes in dirty_log_test
  KVM: selftests: Use host page size to map ring buffer in dirty_log_test
  KVM: arm64: Enable ring-based dirty memory tracking
  KVM: Support dirty ring in conjunction with bitmap
  KVM: Move declaration of kvm_cpu_dirty_log_size() to kvm_dirty_ring.h
  KVM: x86: Introduce KVM_REQ_DIRTY_RING_SOFT_FULL

Signed-off-by: Marc Zyngier <maz@kernel.org>
2022-12-05 14:19:50 +00:00