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| author | Sean Christopherson <seanjc@google.com> | 2024-02-09 14:17:00 -0800 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2024-04-09 10:24:36 -0700 |
| commit | 23ffe4bbf807c34cd5374f3e53196ccc459707f4 (patch) | |
| tree | 00b6aeb1816d8f4e9c52feef10ddd3b34caa80c0 /arch/x86 | |
| parent | a9466078687fb740298a52a095ee4832738efbea (diff) | |
| download | linux-stable-23ffe4bbf807c34cd5374f3e53196ccc459707f4.tar.gz linux-stable-23ffe4bbf807c34cd5374f3e53196ccc459707f4.tar.bz2 linux-stable-23ffe4bbf807c34cd5374f3e53196ccc459707f4.zip | |
KVM: nVMX: Add a sanity check that nested PML Full stems from EPT Violations
Add a WARN_ON_ONCE() sanity check to verify that a nested PML Full VM-Exit
is only synthesized when the original VM-Exit from L2 was an EPT Violation.
While KVM can fallthrough to kvm_mmu_do_page_fault() if an EPT Misconfig
occurs on a stale MMIO SPTE, KVM should not treat the access as a write
(there isn't enough information to know *what* the access was), i.e. KVM
should never try to insert a PML entry in that case.
Link: https://lore.kernel.org/r/20240209221700.393189-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kvm/vmx/nested.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index cebbc4d47000..d5b832126e34 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -417,6 +417,16 @@ static void nested_ept_inject_page_fault(struct kvm_vcpu *vcpu, vmx->nested.pml_full = false; /* + * It should be impossible to trigger a nested PML Full VM-Exit + * for anything other than an EPT Violation from L2. KVM *can* + * trigger nEPT page fault injection in response to an EPT + * Misconfig, e.g. if the MMIO SPTE was stale and L1's EPT + * tables also changed, but KVM should not treat EPT Misconfig + * VM-Exits as writes. + */ + WARN_ON_ONCE(vmx->exit_reason.basic != EXIT_REASON_EPT_VIOLATION); + + /* * PML Full and EPT Violation VM-Exits both use bit 12 to report * "NMI unblocking due to IRET", i.e. the bit can be propagated * as-is from the original EXIT_QUALIFICATION. |