263 Commits

Author SHA1 Message Date
Sean Christopherson
7b7bd87dbd KVM: nVMX: Uninline nested_vmx_reflect_vmexit(), i.e. move it to nested.c
Uninline nested_vmx_reflect_vmexit() in preparation of refactoring
nested_vmx_exit_reflected() to split up the reflection logic into more
consumable chunks, e.g. VM-Fail vs. L1 wants the exit vs. L0 always
handles the exit.

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200415175519.14230-3-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-04-21 09:13:02 -04:00
Sean Christopherson
be01e8e2c6 KVM: x86: Replace "cr3" with "pgd" in "new cr3/pgd" related code
Rename functions and variables in kvm_mmu_new_cr3() and related code to
replace "cr3" with "pgd", i.e. continue the work started by commit
727a7e27cf88a ("KVM: x86: rename set_cr3 callback and related flags to
load_mmu_pgd").  kvm_mmu_new_cr3() and company are not always loading a
new CR3, e.g. when nested EPT is enabled "cr3" is actually an EPTP.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200320212833.3507-37-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-04-21 09:12:59 -04:00
Sean Christopherson
ce8fe7b77b KVM: nVMX: Free only the affected contexts when emulating INVEPT
Add logic to handle_invept() to free only those roots that match the
target EPT context when emulating a single-context INVEPT.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200320212833.3507-36-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-04-21 09:12:58 -04:00
Sean Christopherson
9805c5f74b KVM: nVMX: Don't flush TLB on nested VMX transition
Unconditionally skip the TLB flush triggered when reusing a root for a
nested transition as nested_vmx_transition_tlb_flush() ensures the TLB
is flushed when needed, regardless of whether the MMU can reuse a cached
root (or the last root).

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200320212833.3507-35-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-04-21 09:12:58 -04:00
Sean Christopherson
41fab65e7c KVM: nVMX: Skip MMU sync on nested VMX transition when possible
Skip the MMU sync when reusing a cached root if EPT is enabled or L1
enabled VPID for L2.

If EPT is enabled, guest-physical mappings aren't flushed even if VPID
is disabled, i.e. L1 can't expect stale TLB entries to be flushed if it
has enabled EPT and L0 isn't shadowing PTEs (for L1 or L2) if L1 has
EPT disabled.

If VPID is enabled (and EPT is disabled), then L1 can't expect stale TLB
entries to be flushed (for itself or L2).

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200320212833.3507-34-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-04-21 09:12:57 -04:00
Sean Christopherson
4a632ac6ca KVM: x86/mmu: Add separate override for MMU sync during fast CR3 switch
Add a separate "skip" override for MMU sync, a future change to avoid
TLB flushes on nested VMX transitions may need to sync the MMU even if
the TLB flush is unnecessary.

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200320212833.3507-32-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-04-21 09:12:56 -04:00
Sean Christopherson
1196cb970b KVM: nVMX: Reload APIC access page on nested VM-Exit only if necessary
Defer reloading L1's APIC page by logging the need for a reload and
processing it during nested VM-Exit instead of unconditionally reloading
the APIC page on nested VM-Exit.  This eliminates a TLB flush on the
majority of VM-Exits as the APIC page rarely needs to be reloaded.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200320212833.3507-28-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-04-21 09:12:54 -04:00
Sean Christopherson
c51e1ffee5 KVM: nVMX: Selectively use TLB_FLUSH_CURRENT for nested VM-Enter/VM-Exit
Flush only the current context, as opposed to all contexts, when
requesting a TLB flush to handle the scenario where a L1 does not expect
a TLB flush, but one is required because L1 and L2 shared an ASID.  This
occurs if EPT is disabled (no per-EPTP tag), VPID is enabled (hardware
doesn't flush unconditionally) and vmcs02 does not have its own VPID due
to exhaustion of available VPIDs.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200320212833.3507-27-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-04-21 09:12:54 -04:00
Sean Christopherson
eeeb4f67a6 KVM: x86: Introduce KVM_REQ_TLB_FLUSH_CURRENT to flush current ASID
Add KVM_REQ_TLB_FLUSH_CURRENT to allow optimized TLB flushing of VMX's
EPTP/VPID contexts[*] from the KVM MMU and/or in a deferred manner, e.g.
to flush L2's context during nested VM-Enter.

Convert KVM_REQ_TLB_FLUSH to KVM_REQ_TLB_FLUSH_CURRENT in flows where
the flush is directly associated with vCPU-scoped instruction emulation,
i.e. MOV CR3 and INVPCID.

Add a comment in vmx_vcpu_load_vmcs() above its KVM_REQ_TLB_FLUSH to
make it clear that it deliberately requests a flush of all contexts.

Service any pending flush request on nested VM-Exit as it's possible a
nested VM-Exit could occur after requesting a flush for L2.  Add the
same logic for nested VM-Enter even though it's _extremely_ unlikely
for flush to be pending on nested VM-Enter, but theoretically possible
(in the future) due to RSM (SMM) emulation.

[*] Intel also has an Address Space Identifier (ASID) concept, e.g.
    EPTP+VPID+PCID == ASID, it's just not documented in the SDM because
    the rules of invalidation are different based on which piece of the
    ASID is being changed, i.e. whether the EPTP, VPID, or PCID context
    must be invalidated.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200320212833.3507-25-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-04-21 09:12:53 -04:00
Sean Christopherson
50b265a4ee KVM: nVMX: Add helper to handle TLB flushes on nested VM-Enter/VM-Exit
Add a helper to determine whether or not a full TLB flush needs to be
performed on nested VM-Enter/VM-Exit, as the logic is identical for both
flows and needs a fairly beefy comment to boot.  This also provides a
common point to make future adjustments to the logic.

Handle vpid12 changes the new helper as well even though it is specific
to VM-Enter.  The vpid12 logic is an extension of the flushing logic,
and it's worth the extra bool parameter to provide a single location for
the flushing logic.

Cc: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200320212833.3507-24-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-04-21 09:12:52 -04:00
Sean Christopherson
25d8b84376 KVM: nVMX: Move nested_get_vpid02() to vmx/nested.h
Move nested_get_vpid02() to vmx/nested.h so that a future patch can
reference it from vmx.c to implement context-specific TLB flushing.

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200320212833.3507-20-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-04-21 09:12:51 -04:00
Sean Christopherson
bc41d0c40e KVM: nVMX: Use vpid_sync_vcpu_addr() to emulate INVVPID with address
Use vpid_sync_vcpu_addr() to emulate the "individual address" variant of
INVVPID now that said function handles the fallback case of the (host)
CPU not supporting "individual address".

Note, the "vpid == 0" checks in the vpid_sync_*() helpers aren't
actually redundant with the "!operand.vpid" check in handle_invvpid(),
as the vpid passed to vpid_sync_vcpu_addr() is a KVM (host) controlled
value, i.e. vpid02 can be zero even if operand.vpid is non-zero.

No functional change intended.

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200320212833.3507-14-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-04-20 17:26:09 -04:00
Sean Christopherson
446ace4bca KVM: VMX: Use vpid_sync_context() directly when possible
Use vpid_sync_context() directly for flows that run if and only if
enable_vpid=1, or more specifically, nested VMX flows that are gated by
vmx->nested.msrs.secondary_ctls_high.SECONDARY_EXEC_ENABLE_VPID being
set, which is allowed if and only if enable_vpid=1.  Because these flows
call __vmx_flush_tlb() with @invalidate_gpa=false, the if-statement that
decides between INVEPT and INVVPID will always go down the INVVPID path,
i.e. call vpid_sync_context() because
"enable_ept && (invalidate_gpa || !enable_vpid)" always evaluates false.

This helps pave the way toward removing @invalidate_gpa and @vpid from
__vmx_flush_tlb() and its callers.

Opportunstically drop unnecessary brackets in handle_invvpid() around an
affected __vmx_flush_tlb()->vpid_sync_context() conversion.

No functional change intended.

Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200320212833.3507-10-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-04-20 17:26:06 -04:00
Junaid Shahid
ee1fa209f5 KVM: x86: Sync SPTEs when injecting page/EPT fault into L1
When injecting a page fault or EPT violation/misconfiguration, KVM is
not syncing any shadow PTEs associated with the faulting address,
including those in previous MMUs that are associated with L1's current
EPTP (in a nested EPT scenario), nor is it flushing any hardware TLB
entries.  All this is done by kvm_mmu_invalidate_gva.

Page faults that are either !PRESENT or RSVD are exempt from the flushing,
as the CPU is not allowed to cache such translations.

Signed-off-by: Junaid Shahid <junaids@google.com>
Co-developed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200320212833.3507-8-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-04-20 17:26:05 -04:00
Junaid Shahid
d6e3f8385d KVM: nVMX: Invalidate all roots when emulating INVVPID without EPT
Free all roots when emulating INVVPID for L1 and EPT is disabled, as
outstanding changes to the page tables managed by L1 need to be
recognized.  Because L1 and L2 share an MMU when EPT is disabled, and
because VPID is not tracked by the MMU role, all roots in the current
MMU (root_mmu) need to be freed, otherwise a future nested VM-Enter or
VM-Exit could do a fast CR3 switch (without a flush/sync) and consume
stale SPTEs.

Fixes: 5c614b3583e7b ("KVM: nVMX: nested VPID emulation")
Signed-off-by: Junaid Shahid <junaids@google.com>
[sean: ported to upstream KVM, reworded the comment and changelog]
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200320212833.3507-5-sean.j.christopherson@intel.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-04-15 12:08:49 -04:00
Sean Christopherson
f8aa7e3958 KVM: nVMX: Invalidate all EPTP contexts when emulating INVEPT for L1
Free all L2 (guest_mmu) roots when emulating INVEPT for L1.  Outstanding
changes to the EPT tables managed by L1 need to be recognized, and
relying on KVM to always flush L2's EPTP context on nested VM-Enter is
dangerous.

Similar to handle_invpcid(), rely on kvm_mmu_free_roots() to do a remote
TLB flush if necessary, e.g. if L1 has never entered L2 then there is
nothing to be done.

Nuking all L2 roots is overkill for the single-context variant, but it's
the safe and easy bet.  A more precise zap mechanism will be added in
the future.  Add a TODO to call out that KVM only needs to invalidate
affected contexts.

Fixes: 14c07ad89f4d ("x86/kvm/mmu: introduce guest_mmu")
Reported-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200320212833.3507-4-sean.j.christopherson@intel.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-04-15 12:08:49 -04:00
Sean Christopherson
eed0030e4c KVM: nVMX: Validate the EPTP when emulating INVEPT(EXTENT_CONTEXT)
Signal VM-Fail for the single-context variant of INVEPT if the specified
EPTP is invalid.  Per the INEVPT pseudocode in Intel's SDM, it's subject
to the standard EPT checks:

  If VM entry with the "enable EPT" VM execution control set to 1 would
  fail due to the EPTP value then VMfail(Invalid operand to INVEPT/INVVPID);

Fixes: bfd0a56b90005 ("nEPT: Nested INVEPT")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200320212833.3507-3-sean.j.christopherson@intel.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-04-15 12:08:48 -04:00
Oliver Upton
69c0975525 kvm: nVMX: match comment with return type for nested_vmx_exit_reflected
nested_vmx_exit_reflected() returns a bool, not int. As such, refer to
the return values as true/false in the comment instead of 1/0.

Signed-off-by: Oliver Upton <oupton@google.com>
Message-Id: <20200414221241.134103-1-oupton@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-04-15 12:08:35 -04:00
Oliver Upton
b045ae906b kvm: nVMX: reflect MTF VM-exits if injected by L1
According to SDM 26.6.2, it is possible to inject an MTF VM-exit via the
VM-entry interruption-information field regardless of the 'monitor trap
flag' VM-execution control. KVM appropriately copies the VM-entry
interruption-information field from vmcs12 to vmcs02. However, if L1
has not set the 'monitor trap flag' VM-execution control, KVM fails to
reflect the subsequent MTF VM-exit into L1.

Fix this by consulting the VM-entry interruption-information field of
vmcs12 to determine if L1 has injected the MTF VM-exit. If so, reflect
the exit, regardless of the 'monitor trap flag' VM-execution control.

Fixes: 5f3d45e7f282 ("kvm/x86: add support for MONITOR_TRAP_FLAG")
Signed-off-by: Oliver Upton <oupton@google.com>
Reviewed-by: Peter Shier <pshier@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Message-Id: <20200414224746.240324-1-oupton@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-04-15 12:08:35 -04:00
Oliver Upton
5c8beb4746 KVM: nVMX: don't clear mtf_pending when nested events are blocked
If nested events are blocked, don't clear the mtf_pending flag to avoid
missing later delivery of the MTF VM-exit.

Fixes: 5ef8acbdd687c ("KVM: nVMX: Emulate MTF when performing instruction emulation")
Signed-off-by: Oliver Upton <oupton@google.com>
Message-Id: <20200406201237.178725-1-oupton@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-04-07 04:21:41 -04:00
Sean Christopherson
afaf0b2f9b KVM: x86: Copy kvm_x86_ops by value to eliminate layer of indirection
Replace the kvm_x86_ops pointer in common x86 with an instance of the
struct to save one pointer dereference when invoking functions.  Copy the
struct by value to set the ops during kvm_init().

Arbitrarily use kvm_x86_ops.hardware_enable to track whether or not the
ops have been initialized, i.e. a vendor KVM module has been loaded.

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200321202603.19355-7-sean.j.christopherson@intel.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-31 10:48:08 -04:00
Sean Christopherson
72b0eaa946 KVM: VMX: Configure runtime hooks using vmx_x86_ops
Configure VMX's runtime hooks by modifying vmx_x86_ops directly instead
of using the global kvm_x86_ops.  This sets the stage for waiting until
after ->hardware_setup() to set kvm_x86_ops with the vendor's
implementation.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200321202603.19355-5-sean.j.christopherson@intel.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-31 10:48:06 -04:00
Paolo Bonzini
96b100cd14 KVM: nVMX: remove side effects from nested_vmx_exit_reflected
The name of nested_vmx_exit_reflected suggests that it's purely
a test, but it actually marks VMCS12 pages as dirty.  Move this to
vmx_handle_exit, observing that the initial nested_run_pending check in
nested_vmx_exit_reflected is pointless---nested_run_pending has just
been cleared in vmx_vcpu_run and won't be set until handle_vmlaunch
or handle_vmresume.

Suggested-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-18 12:16:39 +01:00
Vitaly Kuznetsov
b6a0653ae2 KVM: nVMX: properly handle errors in nested_vmx_handle_enlightened_vmptrld()
nested_vmx_handle_enlightened_vmptrld() fails in two cases:
- when we fail to kvm_vcpu_map() the supplied GPA
- when revision_id is incorrect.
Genuine Hyper-V raises #UD in the former case (at least with *some*
incorrect GPAs) and does VMfailInvalid() in the later. KVM doesn't do
anything so L1 just gets stuck retrying the same faulty VMLAUNCH.

nested_vmx_handle_enlightened_vmptrld() has two call sites:
nested_vmx_run() and nested_get_vmcs12_pages(). The former needs to queue
do much: the failure there happens after migration when L2 was running (and
L1 did something weird like wrote to VP assist page from a different vCPU),
just kill L1 with KVM_EXIT_INTERNAL_ERROR.

Reported-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
[Squash kbuild autopatch. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 18:19:30 +01:00
Vitaly Kuznetsov
e942dbf8c5 KVM: nVMX: stop abusing need_vmcs12_to_shadow_sync for eVMCS mapping
When vmx_set_nested_state() happens, we may not have all the required
data to map enlightened VMCS: e.g. HV_X64_MSR_VP_ASSIST_PAGE MSR may not
yet be restored so we need a postponed action. Currently, we (ab)use
need_vmcs12_to_shadow_sync/nested_sync_vmcs12_to_shadow() for that but
this is not ideal:
- We may not need to sync anything if L2 is running
- It is hard to propagate errors from nested_sync_vmcs12_to_shadow()
 as we call it from vmx_prepare_switch_to_guest() which happens just
 before we do VMLAUNCH, the code is not ready to handle errors there.

Move eVMCS mapping to nested_get_vmcs12_pages() and request
KVM_REQ_GET_VMCS12_PAGES, it seems to be is less abusive in nature.
It would probably be possible to introduce a specialized KVM_REQ_EVMCS_MAP
but it is undesirable to propagate eVMCS specifics all the way up to x86.c

Note, we don't need to request KVM_REQ_GET_VMCS12_PAGES from
vmx_set_nested_state() directly as nested_vmx_enter_non_root_mode() already
does that. Requesting KVM_REQ_GET_VMCS12_PAGES is done to document the
(non-obvious) side-effect and to be future proof.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 18:19:29 +01:00
Paolo Bonzini
0c546725ee Merge branch 'kvm-null-pointer-fix' into HEAD 2020-03-16 17:59:11 +01:00
Oliver Upton
212617dbb6 KVM: nVMX: Consolidate nested MTF checks to helper function
commit 5ef8acbdd687 ("KVM: nVMX: Emulate MTF when performing
instruction emulation") introduced a helper to check the MTF
VM-execution control in vmcs12. Change pre-existing check in
nested_vmx_exit_reflected() to instead use the helper.

Signed-off-by: Oliver Upton <oupton@google.com>
Reviewed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:58:59 +01:00
Paolo Bonzini
727a7e27cf KVM: x86: rename set_cr3 callback and related flags to load_mmu_pgd
The set_cr3 callback is not setting the guest CR3, it is setting the
root of the guest page tables, either shadow or two-dimensional.
To make this clearer as well as to indicate that the MMU calls it
via kvm_mmu_load_cr3, rename it to load_mmu_pgd.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:58:52 +01:00
Paolo Bonzini
689f3bf216 KVM: x86: unify callbacks to load paging root
Similar to what kvm-intel.ko is doing, provide a single callback that
merges svm_set_cr3, set_tdp_cr3 and nested_svm_set_tdp_cr3.

This lets us unify the set_cr3 and set_tdp_cr3 entries in kvm_x86_ops.
I'm doing that in this same patch because splitting it adds quite a bit
of churn due to the need for forward declarations.  For the same reason
the assignment to vcpu->arch.mmu->set_cr3 is moved to kvm_init_shadow_mmu
from init_kvm_softmmu and nested_svm_init_mmu_context.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:58:51 +01:00
Sean Christopherson
2ef7619d43 KVM: VMX: Add helpers to query Intel PT mode
Add helpers to query which of the (two) supported PT modes is active.
The primary motivation is to help document that there is a third PT mode
(host-only) that's currently not supported by KVM.  As is, it's not
obvious that PT_MODE_SYSTEM != !PT_MODE_HOST_GUEST and vice versa, e.g.
that "pt_mode == PT_MODE_SYSTEM" and "pt_mode != PT_MODE_HOST_GUEST" are
two distinct checks.

No functional change intended.

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:58:08 +01:00
Sean Christopherson
96d4701049 KVM: nVMX: Drop unnecessary check on ept caps for execute-only
Drop the call to cpu_has_vmx_ept_execute_only() when calculating which
EPT capabilities will be exposed to L1 for nested EPT.  The resulting
configuration is immediately sanitized by the passed in @ept_caps, and
except for the call from vmx_check_processor_compat(), @ept_caps is the
capabilities that are queried by cpu_has_vmx_ept_execute_only().  For
vmx_check_processor_compat(), KVM *wants* to ignore vmx_capability.ept
so that a divergence in EPT capabilities between CPUs is detected.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:57:47 +01:00
Sean Christopherson
d8dd54e063 KVM: x86/mmu: Rename kvm_mmu->get_cr3() to ->get_guest_pgd()
Rename kvm_mmu->get_cr3() to call out that it is retrieving a guest
value, as opposed to kvm_mmu->set_cr3(), which sets a host value, and to
note that it will return something other than CR3 when nested EPT is in
use.  Hopefully the new name will also make it more obvious that L1's
nested_cr3 is returned in SVM's nested NPT case.

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:57:46 +01:00
Sean Christopherson
ac6389ab2c KVM: nVMX: Rename EPTP validity helper and associated variables
Rename valid_ept_address() to nested_vmx_check_eptp() to follow the nVMX
nomenclature and to reflect that the function now checks a lot more than
just the address contained in the EPTP.  Rename address to new_eptp in
associated code.

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:57:45 +01:00
Sean Christopherson
ac69dfaace KVM: nVMX: Rename nested_ept_get_cr3() to nested_ept_get_eptp()
Rename the accessor for vmcs12.EPTP to use "eptp" instead of "cr3".  The
accessor has no relation to cr3 whatsoever, other than it being assigned
to the also poorly named kvm_mmu->get_cr3() hook.

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:57:44 +01:00
Sean Christopherson
bb1fcc70d9 KVM: nVMX: Allow L1 to use 5-level page walks for nested EPT
Add support for 5-level nested EPT, and advertise said support in the
EPT capabilities MSR.  KVM's MMU can already handle 5-level legacy page
tables, there's no reason to force an L1 VMM to use shadow paging if it
wants to employ 5-level page tables.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:57:44 +01:00
Sean Christopherson
a1c77abb8d KVM: nVMX: Properly handle userspace interrupt window request
Return true for vmx_interrupt_allowed() if the vCPU is in L2 and L1 has
external interrupt exiting enabled.  IRQs are never blocked in hardware
if the CPU is in the guest (L2 from L1's perspective) when IRQs trigger
VM-Exit.

The new check percolates up to kvm_vcpu_ready_for_interrupt_injection()
and thus vcpu_run(), and so KVM will exit to userspace if userspace has
requested an interrupt window (to inject an IRQ into L1).

Remove the @external_intr param from vmx_check_nested_events(), which is
actually an indicator that userspace wants an interrupt window, e.g.
it's named @req_int_win further up the stack.  Injecting a VM-Exit into
L1 to try and bounce out to L0 userspace is all kinds of broken and is
no longer necessary.

Remove the hack in nested_vmx_vmexit() that attempted to workaround the
breakage in vmx_check_nested_events() by only filling interrupt info if
there's an actual interrupt pending.  The hack actually made things
worse because it caused KVM to _never_ fill interrupt info when the
LAPIC resides in userspace (kvm_cpu_has_interrupt() queries
interrupt.injected, which is always cleared by prepare_vmcs12() before
reaching the hack in nested_vmx_vmexit()).

Fixes: 6550c4df7e50 ("KVM: nVMX: Fix interrupt window request with "Acknowledge interrupt on exit"")
Cc: stable@vger.kernel.org
Cc: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:57:40 +01:00
Miaohe Lin
49f933d445 KVM: Fix some obsolete comments
Remove some obsolete comments, fix wrong function name and description.

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:57:38 +01:00
Miaohe Lin
e630269841 KVM: x86: Fix print format and coding style
Use %u to print u32 var and correct some coding style.

Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:57:08 +01:00
Vitaly Kuznetsov
95fa10103d KVM: nVMX: avoid NULL pointer dereference with incorrect EVMCS GPAs
When an EVMCS enabled L1 guest on KVM will tries doing enlightened VMEnter
with EVMCS GPA = 0 the host crashes because the

evmcs_gpa != vmx->nested.hv_evmcs_vmptr

condition in nested_vmx_handle_enlightened_vmptrld() will evaluate to
false (as nested.hv_evmcs_vmptr is zeroed after init). The crash will
happen on vmx->nested.hv_evmcs pointer dereference.

Another problematic EVMCS ptr value is '-1' but it only causes host crash
after nested_release_evmcs() invocation. The problem is exactly the same as
with '0', we mistakenly think that the EVMCS pointer hasn't changed and
thus nested.hv_evmcs_vmptr is valid.

Resolve the issue by adding an additional !vmx->nested.hv_evmcs
check to nested_vmx_handle_enlightened_vmptrld(), this way we will
always be trying kvm_vcpu_map() when nested.hv_evmcs is NULL
and this is supposed to catch all invalid EVMCS GPAs.

Also, initialize hv_evmcs_vmptr to '0' in nested_release_evmcs()
to be consistent with initialization where we don't currently
set hv_evmcs_vmptr to '-1'.

Cc: stable@vger.kernel.org
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-14 12:49:27 +01:00
Oliver Upton
35a571346a KVM: nVMX: Check IO instruction VM-exit conditions
Consult the 'unconditional IO exiting' and 'use IO bitmaps' VM-execution
controls when checking instruction interception. If the 'use IO bitmaps'
VM-execution control is 1, check the instruction access against the IO
bitmaps to determine if the instruction causes a VM-exit.

Signed-off-by: Oliver Upton <oupton@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-02-23 10:16:32 +01:00
Oliver Upton
e71237d3ff KVM: nVMX: Refactor IO bitmap checks into helper function
Checks against the IO bitmap are useful for both instruction emulation
and VM-exit reflection. Refactor the IO bitmap checks into a helper
function.

Signed-off-by: Oliver Upton <oupton@google.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-02-23 10:14:40 +01:00
Oliver Upton
5ef8acbdd6 KVM: nVMX: Emulate MTF when performing instruction emulation
Since commit 5f3d45e7f282 ("kvm/x86: add support for
MONITOR_TRAP_FLAG"), KVM has allowed an L1 guest to use the monitor trap
flag processor-based execution control for its L2 guest. KVM simply
forwards any MTF VM-exits to the L1 guest, which works for normal
instruction execution.

However, when KVM needs to emulate an instruction on the behalf of an L2
guest, the monitor trap flag is not emulated. Add the necessary logic to
kvm_skip_emulated_instruction() to synthesize an MTF VM-exit to L1 upon
instruction emulation for L2.

Fixes: 5f3d45e7f282 ("kvm/x86: add support for MONITOR_TRAP_FLAG")
Signed-off-by: Oliver Upton <oupton@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-02-23 09:36:23 +01:00
Vitaly Kuznetsov
a444326780 KVM: nVMX: clear PIN_BASED_POSTED_INTR from nested pinbased_ctls only when apicv is globally disabled
When apicv is disabled on a vCPU (e.g. by enabling KVM_CAP_HYPERV_SYNIC*),
nothing happens to VMX MSRs on the already existing vCPUs, however, all new
ones are created with PIN_BASED_POSTED_INTR filtered out. This is very
confusing and results in the following picture inside the guest:

$ rdmsr -ax 0x48d
ff00000016
7f00000016
7f00000016
7f00000016

This is observed with QEMU and 4-vCPU guest: QEMU creates vCPU0, does
KVM_CAP_HYPERV_SYNIC2 and then creates the remaining three.

L1 hypervisor may only check CPU0's controls to find out what features
are available and it will be very confused later. Switch to setting
PIN_BASED_POSTED_INTR control based on global 'enable_apicv' setting.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-02-21 18:05:35 +01:00
Miaohe Lin
463bfeeead KVM: nVMX: Fix some obsolete comments and grammar error
Fix wrong variable names and grammar error in comment.

Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-02-17 12:52:39 +01:00
Miaohe Lin
ffdbd50dca KVM: nVMX: Fix some comment typos and coding style
Fix some typos in the comments. Also fix coding style.
[Sean Christopherson rewrites the comment of write_fault_to_shadow_pgtable
field in struct kvm_vcpu_arch.]

Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-02-12 20:09:43 +01:00
Oliver Upton
684c0422da KVM: nVMX: Handle pending #DB when injecting INIT VM-exit
SDM 27.3.4 states that the 'pending debug exceptions' VMCS field will
be populated if a VM-exit caused by an INIT signal takes priority over a
debug-trap. Emulate this behavior when synthesizing an INIT signal
VM-exit into L1.

Fixes: 4b9852f4f389 ("KVM: x86: Fix INIT signal handling in various CPU states")
Signed-off-by: Oliver Upton <oupton@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-02-12 12:34:09 +01:00
Vitaly Kuznetsov
a83502314c x86/kvm/hyper-v: don't allow to turn on unsupported VMX controls for nested guests
Sane L1 hypervisors are not supposed to turn any of the unsupported VMX
controls on for its guests and nested_vmx_check_controls() checks for
that. This is, however, not the case for the controls which are supported
on the host but are missing in enlightened VMCS and when eVMCS is in use.

It would certainly be possible to add these missing checks to
nested_check_vm_execution_controls()/_vm_exit_controls()/.. but it seems
preferable to keep eVMCS-specific stuff in eVMCS and reduce the impact on
non-eVMCS guests by doing less unrelated checks. Create a separate
nested_evmcs_check_controls() for this purpose.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-02-05 15:55:26 +01:00
Sean Christopherson
ea79a75092 KVM: nVMX: Remove stale comment from nested_vmx_load_cr3()
The blurb pertaining to the return value of nested_vmx_load_cr3() no
longer matches reality, remove it entirely as the behavior it is
attempting to document is quite obvious when reading the actual code.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-02-05 15:31:25 +01:00
Miaohe Lin
33aabd029f KVM: nVMX: delete meaningless nested_vmx_run() declaration
The function nested_vmx_run() declaration is below its implementation. So
this is meaningless and should be removed.

Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-02-05 15:17:45 +01:00
Linus Torvalds
e813e65038 ARM: Cleanups and corner case fixes
PPC: Bugfixes
 
 x86:
 * Support for mapping DAX areas with large nested page table entries.
 * Cleanups and bugfixes here too.  A particularly important one is
 a fix for FPU load when the thread has TIF_NEED_FPU_LOAD.  There is
 also a race condition which could be used in guest userspace to exploit
 the guest kernel, for which the embargo expired today.
 * Fast path for IPI delivery vmexits, shaving about 200 clock cycles
 from IPI latency.
 * Protect against "Spectre-v1/L1TF" (bring data in the cache via
 speculative out of bound accesses, use L1TF on the sibling hyperthread
 to read it), which unfortunately is an even bigger whack-a-mole game
 than SpectreV1.
 
 Sean continues his mission to rewrite KVM.  In addition to a sizable
 number of x86 patches, this time he contributed a pretty large refactoring
 of vCPU creation that affects all architectures but should not have any
 visible effect.
 
 s390 will come next week together with some more x86 patches.
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Merge tag 'kvm-5.6-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull KVM updates from Paolo Bonzini:
 "This is the first batch of KVM changes.

  ARM:
   - cleanups and corner case fixes.

  PPC:
   - Bugfixes

  x86:
   - Support for mapping DAX areas with large nested page table entries.

   - Cleanups and bugfixes here too. A particularly important one is a
     fix for FPU load when the thread has TIF_NEED_FPU_LOAD. There is
     also a race condition which could be used in guest userspace to
     exploit the guest kernel, for which the embargo expired today.

   - Fast path for IPI delivery vmexits, shaving about 200 clock cycles
     from IPI latency.

   - Protect against "Spectre-v1/L1TF" (bring data in the cache via
     speculative out of bound accesses, use L1TF on the sibling
     hyperthread to read it), which unfortunately is an even bigger
     whack-a-mole game than SpectreV1.

  Sean continues his mission to rewrite KVM. In addition to a sizable
  number of x86 patches, this time he contributed a pretty large
  refactoring of vCPU creation that affects all architectures but should
  not have any visible effect.

  s390 will come next week together with some more x86 patches"

* tag 'kvm-5.6-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (204 commits)
  x86/KVM: Clean up host's steal time structure
  x86/KVM: Make sure KVM_VCPU_FLUSH_TLB flag is not missed
  x86/kvm: Cache gfn to pfn translation
  x86/kvm: Introduce kvm_(un)map_gfn()
  x86/kvm: Be careful not to clear KVM_VCPU_FLUSH_TLB bit
  KVM: PPC: Book3S PR: Fix -Werror=return-type build failure
  KVM: PPC: Book3S HV: Release lock on page-out failure path
  KVM: arm64: Treat emulated TVAL TimerValue as a signed 32-bit integer
  KVM: arm64: pmu: Only handle supported event counters
  KVM: arm64: pmu: Fix chained SW_INCR counters
  KVM: arm64: pmu: Don't mark a counter as chained if the odd one is disabled
  KVM: arm64: pmu: Don't increment SW_INCR if PMCR.E is unset
  KVM: x86: Use a typedef for fastop functions
  KVM: X86: Add 'else' to unify fastop and execute call path
  KVM: x86: inline memslot_valid_for_gpte
  KVM: x86/mmu: Use huge pages for DAX-backed files
  KVM: x86/mmu: Remove lpage_is_disallowed() check from set_spte()
  KVM: x86/mmu: Fold max_mapping_level() into kvm_mmu_hugepage_adjust()
  KVM: x86/mmu: Zap any compound page when collapsing sptes
  KVM: x86/mmu: Remove obsolete gfn restoration in FNAME(fetch)
  ...
2020-01-31 09:30:41 -08:00