diff options
| author | Sean Christopherson <seanjc@google.com> | 2022-08-03 22:49:57 +0000 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2022-08-10 15:08:25 -0400 |
| commit | 0c29397ac1fdd64ae59941a477511a05e61a4754 (patch) | |
| tree | 1daff68cc9a54989680768650f50155d0c7002a4 /arch/x86/kvm/mmu/spte.c | |
| parent | c3e0c8c2e8b17bae30d5978bc2decdd4098f0f99 (diff) | |
KVM: SVM: Disable SEV-ES support if MMIO caching is disable
Disable SEV-ES if MMIO caching is disabled as SEV-ES relies on MMIO SPTEs
generating #NPF(RSVD), which are reflected by the CPU into the guest as
a #VC. With SEV-ES, the untrusted host, a.k.a. KVM, doesn't have access
to the guest instruction stream or register state and so can't directly
emulate in response to a #NPF on an emulated MMIO GPA. Disabling MMIO
caching means guest accesses to emulated MMIO ranges cause #NPF(!PRESENT),
and those flavors of #NPF cause automatic VM-Exits, not #VC.
Adjust KVM's MMIO masks to account for the C-bit location prior to doing
SEV(-ES) setup, and document that dependency between adjusting the MMIO
SPTE mask and SEV(-ES) setup.
Fixes: b09763da4dd8 ("KVM: x86/mmu: Add module param to disable MMIO caching (for testing)")
Reported-by: Michael Roth <michael.roth@amd.com>
Tested-by: Michael Roth <michael.roth@amd.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220803224957.1285926-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/mmu/spte.c')
| -rw-r--r-- | arch/x86/kvm/mmu/spte.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/kvm/mmu/spte.c b/arch/x86/kvm/mmu/spte.c index 66f76f5a15bd..03ca740bf721 100644 --- a/arch/x86/kvm/mmu/spte.c +++ b/arch/x86/kvm/mmu/spte.c @@ -22,6 +22,7 @@ bool __read_mostly enable_mmio_caching = true; static bool __ro_after_init allow_mmio_caching; module_param_named(mmio_caching, enable_mmio_caching, bool, 0444); +EXPORT_SYMBOL_GPL(enable_mmio_caching); u64 __read_mostly shadow_host_writable_mask; u64 __read_mostly shadow_mmu_writable_mask; |