diff options
| author | Sean Christopherson <seanjc@google.com> | 2024-06-07 17:11:08 -0700 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2024-06-14 09:20:47 -0700 |
| commit | caa727882937f0d5260a2a026eb7c27d77404066 (patch) | |
| tree | 4600db46f2fd080745203507f515ecef15dc9bf3 | |
| parent | 9ecc1c119b28d28869135a3745541c03965d52be (diff) | |
KVM: x86/mmu: Rephrase comment about synthetic PFERR flags in #PF handler
Reword the BUILD_BUG_ON() comment in the legacy #PF handler to explicitly
describe how asserting that synthetic PFERR flags are limited to bits 31:0
protects KVM against inadvertently passing a synthetic flag to the common
page fault handler.
No functional change intended.
Suggested-by: Xiaoyao Li <xiaoyao.li@intel.com>
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Link: https://lore.kernel.org/r/20240608001108.3296879-1-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
| -rw-r--r-- | arch/x86/kvm/mmu/mmu.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index fd5378b72896..46103e3eda30 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -4552,7 +4552,10 @@ int kvm_handle_page_fault(struct kvm_vcpu *vcpu, u64 error_code, if (WARN_ON_ONCE(error_code >> 32)) error_code = lower_32_bits(error_code); - /* Ensure the above sanity check also covers KVM-defined flags. */ + /* + * Restrict KVM-defined flags to bits 63:32 so that it's impossible for + * them to conflict with #PF error codes, which are limited to 32 bits. + */ BUILD_BUG_ON(lower_32_bits(PFERR_SYNTHETIC_MASK)); vcpu->arch.l1tf_flush_l1d = true; |