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Windows 10/11 guests with Hyper-V role (WSL2) enabled are observed to
hang upon boot or shortly after when a non-default TSC frequency was
set for L1. The issue is observed on a host where TSC scaling is
supported. The problem appears to be that Windows doesn't use TSC
frequency for its guests even when the feature is advertised and KVM
filters SECONDARY_EXEC_TSC_SCALING out when creating L2 controls from
L1's. This leads to L2 running with the default frequency (matching
host's) while L1 is running with an altered one.
Keep SECONDARY_EXEC_TSC_SCALING in secondary exec controls for L2 when
it was set for L1. TSC_MULTIPLIER is already correctly computed and
written by prepare_vmcs02().
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20220712135009.952805-1-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The selftests nested code only supports 4-level paging at the moment.
This means it cannot map nested guest physical addresses with more than
48 bits. Allow perf_test_util nested mode to work on hosts with more
than 48 physical addresses by restricting the guest test region to
48-bits.
While here, opportunistically fix an off-by-one error when dealing with
vm_get_max_gfn(). perf_test_util.c was treating this as the maximum
number of GFNs, rather than the maximum allowed GFN. This didn't result
in any correctness issues, but it did end up shifting the test region
down slightly when using huge pages.
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: David Matlack <dmatlack@google.com>
Message-Id: <20220520233249.3776001-12-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Add an option to dirty_log_perf_test that configures the vCPUs to run in
L2 instead of L1. This makes it possible to benchmark the dirty logging
performance of nested virtualization, which is particularly interesting
because KVM must shadow L1's EPT/NPT tables.
For now this support only works on x86_64 CPUs with VMX. Otherwise
passing -n results in the test being skipped.
Signed-off-by: David Matlack <dmatlack@google.com>
Message-Id: <20220520233249.3776001-11-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Break up the long lines for LIBKVM and alphabetize each architecture.
This makes reading the Makefile easier, and will make reading diffs to
LIBKVM easier.
No functional change intended.
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: David Matlack <dmatlack@google.com>
Message-Id: <20220520233249.3776001-10-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The linker does obey strong/weak symbols when linking static libraries,
it simply resolves an undefined symbol to the first-encountered symbol.
This means that defining __weak arch-generic functions and then defining
arch-specific strong functions to override them in libkvm will not
always work.
More specifically, if we have:
lib/generic.c:
void __weak foo(void)
{
pr_info("weak\n");
}
void bar(void)
{
foo();
}
lib/x86_64/arch.c:
void foo(void)
{
pr_info("strong\n");
}
And a selftest that calls bar(), it will print "weak". Now if you make
generic.o explicitly depend on arch.o (e.g. add function to arch.c that
is called directly from generic.c) it will print "strong". In other
words, it seems that the linker is free to throw out arch.o when linking
because generic.o does not explicitly depend on it, which causes the
linker to lose the strong symbol.
One solution is to link libkvm.a with --whole-archive so that the linker
doesn't throw away object files it thinks are unnecessary. However that
is a bit difficult to plumb since we are using the common selftests
makefile rules. An easier solution is to drop libkvm.a just link
selftests with all the .o files that were originally in libkvm.a.
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: David Matlack <dmatlack@google.com>
Message-Id: <20220520233249.3776001-9-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Drop the "all: $(STATIC_LIBS)" rule. The KVM selftests already depend
on $(STATIC_LIBS), so there is no reason to have an extra "all" rule.
Suggested-by: Peter Xu <peterx@redhat.com>
Signed-off-by: David Matlack <dmatlack@google.com>
Message-Id: <20220520233249.3776001-8-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Create a small helper function to check if a given EPT/VPID capability
is supported. This will be re-used in a follow-up commit to check for 1G
page support.
No functional change intended.
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: David Matlack <dmatlack@google.com>
Message-Id: <20220520233249.3776001-7-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This is a VMX-related macro so move it to vmx.h. While here, open code
the mask like the rest of the VMX bitmask macros.
No functional change intended.
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: David Matlack <dmatlack@google.com>
Message-Id: <20220520233249.3776001-6-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Refactor nested_map() to specify that it explicityl wants 4K mappings
(the existing behavior) and push the implementation down into
__nested_map(), which can be used in subsequent commits to create huge
page mappings.
No function change intended.
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: David Matlack <dmatlack@google.com>
Message-Id: <20220520233249.3776001-5-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
nested_map() does not take a parameter named eptp_memslot. Drop the
comment referring to it.
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: David Matlack <dmatlack@google.com>
Message-Id: <20220520233249.3776001-4-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The current EPT mapping code in the selftests only supports mapping 4K
pages. This commit extends that support with an option to map at 2M or
1G. This will be used in a future commit to create large page mappings
to test eager page splitting.
No functional change intended.
Signed-off-by: David Matlack <dmatlack@google.com>
Message-Id: <20220520233249.3776001-3-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
x86_page_size is an enum used to communicate the desired page size with
which to map a range of memory. Under the hood they just encode the
desired level at which to map the page. This ends up being clunky in a
few ways:
- The name suggests it encodes the size of the page rather than the
level.
- In other places in x86_64/processor.c we just use a raw int to encode
the level.
Simplify this by adopting the kernel style of PG_LEVEL_XX enums and pass
around raw ints when referring to the level. This makes the code easier
to understand since these macros are very common in KVM MMU code.
Signed-off-by: David Matlack <dmatlack@google.com>
Message-Id: <20220520233249.3776001-2-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Commit 74fd41ed16fd ("KVM: x86: nSVM: support PAUSE filtering when L0
doesn't intercept PAUSE") introduced passthrough support for nested pause
filtering, (when the host doesn't intercept PAUSE) (either disabled with
kvm module param, or disabled with '-overcommit cpu-pm=on')
Before this commit, L1 KVM didn't intercept PAUSE at all; afterwards,
the feature was exposed as supported by KVM cpuid unconditionally, thus
if L1 could try to use it even when the L0 KVM can't really support it.
In this case the fallback caused KVM to intercept each PAUSE instruction;
in some cases, such intercept can slow down the nested guest so much
that it can fail to boot. Instead, before the problematic commit KVM
was already setting both thresholds to 0 in vmcb02, but after the first
userspace VM exit shrink_ple_window was called and would reset the
pause_filter_count to the default value.
To fix this, change the fallback strategy - ignore the guest threshold
values, but use/update the host threshold values unless the guest
specifically requests disabling PAUSE filtering (either simple or
advanced).
Also fix a minor bug: on nested VM exit, when PAUSE filter counter
were copied back to vmcb01, a dirty bit was not set.
Thanks a lot to Suravee Suthikulpanit for debugging this!
Fixes: 74fd41ed16fd ("KVM: x86: nSVM: support PAUSE filtering when L0 doesn't intercept PAUSE")
Reported-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Tested-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Co-developed-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20220518072709.730031-1-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Now that these functions are always called with preemption disabled,
remove the preempt_disable()/preempt_enable() pair inside them.
No functional change intended.
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20220606180829.102503-8-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
On SVM, if preemption happens right after the call to finish_rcuwait
but before call to kvm_arch_vcpu_unblocking on SVM/AVIC, it itself
will re-enable AVIC, and then we will try to re-enable it again
in kvm_arch_vcpu_unblocking which will lead to a warning
in __avic_vcpu_load.
The same problem can happen if the vCPU is preempted right after the call
to kvm_arch_vcpu_blocking but before the call to prepare_to_rcuwait
and in this case, we will end up with AVIC enabled during sleep -
Ooops.
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20220606180829.102503-7-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Currently nothing prevents preemption in kvm_vcpu_update_apicv.
On SVM, If the preemption happens after we update the
vcpu->arch.apicv_active, the preemption itself will
'update' the inhibition since the AVIC will be first disabled
on vCPU unload and then enabled, when the current task
is loaded again.
Then we will try to update it again, which will lead to a warning
in __avic_vcpu_load, that the AVIC is already enabled.
Fix this by disabling preemption in this code.
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20220606180829.102503-6-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
There are two issues in avic_kick_target_vcpus_fast
1. It is legal to issue an IPI request with APIC_DEST_NOSHORT
and a physical destination of 0xFF (or 0xFFFFFFFF in case of x2apic),
which must be treated as a broadcast destination.
Fix this by explicitly checking for it.
Also don’t use ‘index’ in this case as it gives no new information.
2. It is legal to issue a logical IPI request to more than one target.
Index field only provides index in physical id table of first
such target and therefore can't be used before we are sure
that only a single target was addressed.
Instead, parse the ICRL/ICRH, double check that a unicast interrupt
was requested, and use that info to figure out the physical id
of the target vCPU.
At that point there is no need to use the index field as well.
In addition to fixing the above issues, also skip the call to
kvm_apic_match_dest.
It is possible to do this now, because now as long as AVIC is not
inhibited, it is guaranteed that none of the vCPUs changed their
apic id from its default value.
This fixes boot of windows guest with AVIC enabled because it uses
IPI with 0xFF destination and no destination shorthand.
Fixes: 7223fd2d5338 ("KVM: SVM: Use target APIC ID to complete AVIC IRQs when possible")
Cc: stable@vger.kernel.org
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20220606180829.102503-5-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
AVIC is now inhibited if the guest changes the apic id,
and therefore this code is no longer needed.
There are several ways this code was broken, including:
1. a vCPU was only allowed to change its apic id to an apic id
of an existing vCPU.
2. After such change, the vCPU whose apic id entry was overwritten,
could not correctly change its own apic id, because its own
entry is already overwritten.
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20220606180829.102503-4-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Neither of these settings should be changed by the guest and it is
a burden to support it in the acceleration code, so just inhibit
this code instead.
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20220606180829.102503-3-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
These days there are too many AVIC/APICv inhibit
reasons, and it doesn't hurt to have some documentation
for them.
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20220606180829.102503-2-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Assign shadow_me_value, not shadow_me_mask, to PAE root entries,
a.k.a. shadow PDPTRs, when host memory encryption is supported. The
"mask" is the set of all possible memory encryption bits, e.g. MKTME
KeyIDs, whereas "value" holds the actual value that needs to be
stuffed into host page tables.
Using shadow_me_mask results in a failed VM-Entry due to setting
reserved PA bits in the PDPTRs, and ultimately causes an OOPS due to
physical addresses with non-zero MKTME bits sending to_shadow_page()
into the weeds:
set kvm_intel.dump_invalid_vmcs=1 to dump internal KVM state.
BUG: unable to handle page fault for address: ffd43f00063049e8
PGD 86dfd8067 P4D 0
Oops: 0000 [#1] PREEMPT SMP
RIP: 0010:mmu_free_root_page+0x3c/0x90 [kvm]
kvm_mmu_free_roots+0xd1/0x200 [kvm]
__kvm_mmu_unload+0x29/0x70 [kvm]
kvm_mmu_unload+0x13/0x20 [kvm]
kvm_arch_destroy_vm+0x8a/0x190 [kvm]
kvm_put_kvm+0x197/0x2d0 [kvm]
kvm_vm_release+0x21/0x30 [kvm]
__fput+0x8e/0x260
____fput+0xe/0x10
task_work_run+0x6f/0xb0
do_exit+0x327/0xa90
do_group_exit+0x35/0xa0
get_signal+0x911/0x930
arch_do_signal_or_restart+0x37/0x720
exit_to_user_mode_prepare+0xb2/0x140
syscall_exit_to_user_mode+0x16/0x30
do_syscall_64+0x4e/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xae
Fixes: e54f1ff244ac ("KVM: x86/mmu: Add shadow_me_value and repurpose shadow_me_mask")
Signed-off-by: Yuan Yao <yuan.yao@intel.com>
Reviewed-by: Kai Huang <kai.huang@intel.com>
Message-Id: <20220608012015.19566-1-yuan.yao@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
- Properly reset the SVE/SME flags on vcpu load
- Fix a vgic-v2 regression regarding accessing the pending
state of a HW interrupt from userspace (and make the code
common with vgic-v3)
- Fix access to the idreg range for protected guests
- Ignore 'kvm-arm.mode=protected' when using VHE
- Return an error from kvm_arch_init_vm() on allocation failure
- A bunch of small cleanups (comments, annotations, indentation)
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Merge tag 'kvmarm-fixes-5.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD
KVM/arm64 fixes for 5.19, take #1
- Properly reset the SVE/SME flags on vcpu load
- Fix a vgic-v2 regression regarding accessing the pending
state of a HW interrupt from userspace (and make the code
common with vgic-v3)
- Fix access to the idreg range for protected guests
- Ignore 'kvm-arm.mode=protected' when using VHE
- Return an error from kvm_arch_init_vm() on allocation failure
- A bunch of small cleanups (comments, annotations, indentation)
The layout of 'struct kvm_vcpu_arch' has evolved significantly since
the initial port of KVM/arm64, so remove the stale comment suggesting
that a prefix of the structure is used exclusively from assembly code.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220609121223.2551-7-will@kernel.org
host_stage2_try() asserts that the KVM host lock is held, so there's no
need to duplicate the assertion in its wrappers.
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220609121223.2551-6-will@kernel.org
has_vhe() expands to a compile-time constant when evaluated from the VHE
or nVHE code, alternatively checking a static key when called from
elsewhere in the kernel. On face value, this looks like a case of
premature optimization, but in fact this allows symbol references on
VHE-specific code paths to be dropped from the nVHE object.
Expand the comment in has_vhe() to make this clearer, hopefully
discouraging anybody from simplifying the code.
Cc: David Brazdil <dbrazdil@google.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220609121223.2551-5-will@kernel.org
Ignore 'kvm-arm.mode=protected' when using VHE so that kvm_get_mode()
only returns KVM_MODE_PROTECTED on systems where the feature is available.
Cc: David Brazdil <dbrazdil@google.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220609121223.2551-4-will@kernel.org
A protected VM accessing ID_AA64ISAR2_EL1 gets punished with an UNDEF,
while it really should only get a zero back if the register is not
handled by the hypervisor emulation (as mandated by the architecture).
Introduce all the missing ID registers (including the unallocated ones),
and have them to return 0.
Reported-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220609121223.2551-3-will@kernel.org
If we fail to allocate the 'supported_cpus' cpumask in kvm_arch_init_vm()
then be sure to return -ENOMEM instead of success (0) on the failure
path.
Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220609121223.2551-2-will@kernel.org
Commit fed9b26b2501 ("MAINTAINERS: Update KVM RISC-V entry to cover
selftests support") optimistically adds a file entry for
tools/testing/selftests/kvm/riscv/, but this directory does not exist.
Hence, ./scripts/get_maintainer.pl --self-test=patterns complains about a
broken reference. The script is very useful to keep MAINTAINERS up to date
and MAINTAINERS can be kept in a state where the script emits no warning.
So, just drop the non-matching file entry rather than starting to collect
exceptions of entries that may match in some close or distant future.
Fixes: fed9b26b2501 ("MAINTAINERS: Update KVM RISC-V entry to cover selftests support")
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Anup Patel <anup@brainfault.org>
Various spelling mistakes in comments.
Detected with the help of Coccinelle.
Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
Signed-off-by: Anup Patel <anup@brainfault.org>
A recurrent bug in the KVM/arm64 code base consists in trying to
access the timer pending state outside of the vcpu context, which
makes zero sense (the pending state only exists when the vcpu
is loaded).
In order to avoid more embarassing crashes and catch the offenders
red-handed, add a warning to kvm_arch_timer_get_input_level() and
return the state as non-pending. This avoids taking the system down,
and still helps tracking down silly bugs.
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220607131427.1164881-4-maz@kernel.org
Now that GICv2 has a proper userspace accessor for the pending state,
switch GICv3 over to it, dropping the local version, moving over the
specific behaviours that CGIv3 requires (such as the distinction
between pending latch and line level which were never enforced
with GICv2).
We also gain extra locking that isn't really necessary for userspace,
but that's a small price to pay for getting rid of superfluous code.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Link: https://lore.kernel.org/r/20220607131427.1164881-3-maz@kernel.org
If a vCPU is outside guest mode and is scheduled out, it might be in the
process of making a memory access. A problem occurs if another vCPU uses
the PV TLB flush feature during the period when the vCPU is scheduled
out, and a virtual address has already been translated but has not yet
been accessed, because this is equivalent to using a stale TLB entry.
To avoid this, only report a vCPU as preempted if sure that the guest
is at an instruction boundary. A rescheduling request will be delivered
to the host physical CPU as an external interrupt, so for simplicity
consider any vmexit *not* instruction boundary except for external
interrupts.
It would in principle be okay to report the vCPU as preempted also
if it is sleeping in kvm_vcpu_block(): a TLB flush IPI will incur the
vmentry/vmexit overhead unnecessarily, and optimistic spinning is
also unlikely to succeed. However, leave it for later because right
now kvm_vcpu_check_block() is doing memory accesses. Even
though the TLB flush issue only applies to virtual memory address,
it's very much preferrable to be conservative.
Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Similar to the Xen path, only change the vCPU's reported state if the vCPU
was actually preempted. The reason for KVM's behavior is that for example
optimistic spinning might not be a good idea if the guest is doing repeated
exits to userspace; however, it is confusing and unlikely to make a difference,
because well-tuned guests will hardly ever exit KVM_RUN in the first place.
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
SVM uses a per-cpu variable to cache the current value of the
tsc scaling multiplier msr on each cpu.
Commit 1ab9287add5e2
("KVM: X86: Add vendor callbacks for writing the TSC multiplier")
broke this caching logic.
Refactor the code so that all TSC scaling multiplier writes go through
a single function which checks and updates the cache.
This fixes the following scenario:
1. A CPU runs a guest with some tsc scaling ratio.
2. New guest with different tsc scaling ratio starts on this CPU
and terminates almost immediately.
This ensures that the short running guest had set the tsc scaling ratio just
once when it was set via KVM_SET_TSC_KHZ. Due to the bug,
the per-cpu cache is not updated.
3. The original guest continues to run, it doesn't restore the msr
value back to its own value, because the cache matches,
and thus continues to run with a wrong tsc scaling ratio.
Fixes: 1ab9287add5e2 ("KVM: X86: Add vendor callbacks for writing the TSC multiplier")
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20220606181149.103072-1-mlevitsk@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
hyperv_clock doesn't always give a stable test result, especially with
AMD CPUs. The test compares Hyper-V MSR clocksource (acquired either
with rdmsr() from within the guest or KVM_GET_MSRS from the host)
against rdtsc(). To increase the accuracy, increase the measured delay
(done with nop loop) by two orders of magnitude and take the mean rdtsc()
value before and after rdmsr()/KVM_GET_MSRS.
Reported-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Tested-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20220601144322.1968742-1-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Currently disabling dirty logging with the TDP MMU is extremely slow.
On a 96 vCPU / 96G VM backed with gigabyte pages, it takes ~200 seconds
to disable dirty logging with the TDP MMU, as opposed to ~4 seconds with
the shadow MMU.
When disabling dirty logging, zap non-leaf parent entries to allow
replacement with huge pages instead of recursing and zapping all of the
child, leaf entries. This reduces the number of TLB flushes required.
and reduces the disable dirty log time with the TDP MMU to ~3 seconds.
Opportunistically add a WARN() to catch GFNs that are mapped at a
higher level than their max level.
Signed-off-by: Ben Gardon <bgardon@google.com>
Message-Id: <20220525230904.1584480-1-bgardon@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
As noted (and fixed) a couple of times in the past, "=@cc<cond>" outputs
and clobbering of "cc" don't work well together. The compiler appears to
mean to reject such, but doesn't - in its upstream form - quite manage
to yet for "cc". Furthermore two similar macros don't clobber "cc", and
clobbering "cc" is pointless in asm()-s for x86 anyway - the compiler
always assumes status flags to be clobbered there.
Fixes: 989b5db215a2 ("x86/uaccess: Implement macros for CMPXCHG on user addresses")
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Message-Id: <485c0c0b-a3a7-0b7c-5264-7d00c01de032@suse.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
When freeing obsolete previous roots, check prev_roots as intended, not
the current root.
Signed-off-by: Shaoqin Huang <shaoqin.huang@intel.com>
Fixes: 527d5cd7eece ("KVM: x86/mmu: Zap only obsolete roots if a root shadow page is zapped")
Message-Id: <20220607005905.2933378-1-shaoqin.huang@intel.com>
Cc: stable@vger.kernel.org
Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Since 5bfa685e62e9 ("KVM: arm64: vgic: Read HW interrupt pending state
from the HW"), we're able to source the pending bit for an interrupt
that is stored either on the physical distributor or on a device.
However, this state is only available when the vcpu is loaded,
and is not intended to be accessed from userspace. Unfortunately,
the GICv2 emulation doesn't provide specific userspace accessors,
and we fallback with the ones that are intended for the guest,
with fatal consequences.
Add a new vgic_uaccess_read_pending() accessor for userspace
to use, build on top of the existing vgic_mmio_read_pending().
Reported-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Tested-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Fixes: 5bfa685e62e9 ("KVM: arm64: vgic: Read HW interrupt pending state from the HW")
Link: https://lore.kernel.org/r/20220607131427.1164881-2-maz@kernel.org
Cc: stable@vger.kernel.org
A livepatch transition may stall indefinitely when a kvm vCPU is heavily
loaded. To the host, the vCPU task is a user thread which is spending a
very long time in the ioctl(KVM_RUN) syscall. During livepatch
transition, set_notify_signal() will be called on such tasks to
interrupt the syscall so that the task can be transitioned. This
interrupts guest execution, but when xfer_to_guest_mode_work() sees that
TIF_NOTIFY_SIGNAL is set but not TIF_SIGPENDING it concludes that an
exit to user mode is unnecessary, and guest execution is resumed without
transitioning the task for the livepatch.
This handling of TIF_NOTIFY_SIGNAL is incorrect, as set_notify_signal()
is expected to break tasks out of interruptible kernel loops and cause
them to return to userspace. Change xfer_to_guest_mode_work() to handle
TIF_NOTIFY_SIGNAL the same as TIF_SIGPENDING, signaling to the vCPU run
loop that an exit to userpsace is needed. Any pending task_work will be
run when get_signal() is called from exit_to_user_mode_loop(), so there
is no longer any need to run task work from xfer_to_guest_mode_work().
Suggested-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Petr Mladek <pmladek@suse.com>
Signed-off-by: Seth Forshee <sforshee@digitalocean.com>
Message-Id: <20220504180840.2907296-1-sforshee@digitalocean.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
A KVM device cleanup happens in either of two callbacks:
1) destroy() which is called when the VM is being destroyed;
2) release() which is called when a device fd is closed.
Most KVM devices use 1) but Book3s's interrupt controller KVM devices
(XICS, XIVE, XIVE-native) use 2) as they need to close and reopen during
the machine execution. The error handling in kvm_ioctl_create_device()
assumes destroy() is always defined which leads to NULL dereference as
discovered by Syzkaller.
This adds a checks for destroy!=NULL and adds a missing release().
This is not changing kvm_destroy_devices() as devices with defined
release() should have been removed from the KVM devices list by then.
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
On each vcpu load, we set the KVM_ARM64_HOST_SME_ENABLED
flag if SME is enabled for EL0 on the host. This is used to
restore the correct state on vpcu put.
However, it appears that nothing ever clears this flag. Once
set, it will stick until the vcpu is destroyed, which has the
potential to spuriously enable SME for userspace. As it turns
out, this is due to the SME code being more or less copied from
SVE, and inheriting the same shortcomings.
We never saw the issue because nothing uses SME, and the amount
of testing is probably still pretty low.
Fixes: 861262ab8627 ("KVM: arm64: Handle SME host state when running guests")
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviwed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220528113829.1043361-3-maz@kernel.org
On each vcpu load, we set the KVM_ARM64_HOST_SVE_ENABLED
flag if SVE is enabled for EL0 on the host. This is used to restore
the correct state on vpcu put.
However, it appears that nothing ever clears this flag. Once
set, it will stick until the vcpu is destroyed, which has the
potential to spuriously enable SVE for userspace.
We probably never saw the issue because no VMM uses SVE, but
that's still pretty bad. Unconditionally clearing the flag
on vcpu load addresses the issue.
Fixes: 8383741ab2e7 ("KVM: arm64: Get rid of host SVE tracking/saving")
Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: stable@vger.kernel.org
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220528113829.1043361-2-maz@kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Merge tag 'pull-work.fd-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull file descriptor fix from Al Viro:
"Fix for breakage in #work.fd this window"
* tag 'pull-work.fd-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
fix the breakage in close_fd_get_file() calling conventions change
- fixes for material merged during this merge window
- cc:stable fixes for more longstanding issues
- minor mailmap and MAINTAINERS updates
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Merge tag 'mm-hotfixes-stable-2022-06-05' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull mm hotfixes from Andrew Morton:
"Fixups for various recently-added and longer-term issues and a few
minor tweaks:
- fixes for material merged during this merge window
- cc:stable fixes for more longstanding issues
- minor mailmap and MAINTAINERS updates"
* tag 'mm-hotfixes-stable-2022-06-05' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
mm/oom_kill.c: fix vm_oom_kill_table[] ifdeffery
x86/kexec: fix memory leak of elf header buffer
mm/memremap: fix missing call to untrack_pfn() in pagemap_range()
mm: page_isolation: use compound_nr() correctly in isolate_single_pageblock()
mm: hugetlb_vmemmap: fix CONFIG_HUGETLB_PAGE_FREE_VMEMMAP_DEFAULT_ON
MAINTAINERS: add maintainer information for z3fold
mailmap: update Josh Poimboeuf's email
because,unusually, it has dependencies on both the mm-stable and
mm-nonmm-stable queues.
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Merge tag 'mm-nonmm-stable-2022-06-05' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull delay-accounting update from Andrew Morton:
"A single featurette for delay accounting.
Delayed a bit because, unusually, it had dependencies on both the
mm-stable and mm-nonmm-stable queues"
* tag 'mm-nonmm-stable-2022-06-05' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
delayacct: track delays from write-protect copy
