iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

KVM: SVM: Treat all "skip" emulation for SEV guests as outright failures

Browse Source 
Treat EMULTYPE_SKIP failures on SEV guests as unhandleable emulation
instead of simply resuming the guest, and drop the hack-a-fix which
effects that behavior for the INT3/INTO injection path.  If KVM can't
skip an instruction for which KVM has already done partial emulation,
resuming the guest is undesirable as doing so may corrupt guest state.

Link: https://lore.kernel.org/r/20230825013621.2845700-5-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
This commit is contained in:
Sean Christopherson 2023-08-24 18:36:21 -07:00
parent aeb904f6b9
commit 0068299540
2 changed files with 8 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
arch/x86/kvm/svm/svm.c
View File

@ -364,8 +364,6 @@ static void svm_set_interrupt_shadow(struct kvm_vcpu *vcpu, int mask)
svm->vmcb->control.int_state |= SVM_INTERRUPT_SHADOW_MASK;
}
static int svm_check_emulate_instruction(struct kvm_vcpu *vcpu, int emul_type,
void *insn, int insn_len);
static int __svm_skip_emulated_instruction(struct kvm_vcpu *vcpu,
bool commit_side_effects)
@ -386,14 +384,6 @@ static int __svm_skip_emulated_instruction(struct kvm_vcpu *vcpu,
}
if (!svm->next_rip) {
/*
* FIXME: Drop this when kvm_emulate_instruction() does the
* right thing and treats "can't emulate" as outright failure
* for EMULTYPE_SKIP.
*/
if (svm_check_emulate_instruction(vcpu, EMULTYPE_SKIP, NULL, 0) != X86EMUL_CONTINUE)
return 0;
if (unlikely(!commit_side_effects))
old_rflags = svm->vmcb->save.rflags;
@ -4781,7 +4771,7 @@ static int svm_check_emulate_instruction(struct kvm_vcpu *vcpu, int emul_type,
*/
if (unlikely(!insn)) {
if (emul_type & EMULTYPE_SKIP)
return X86EMUL_RETRY_INSTR;
return X86EMUL_UNHANDLEABLE;
kvm_queue_exception(vcpu, UD_VECTOR);
return X86EMUL_PROPAGATE_FAULT;

9
arch/x86/kvm/x86.c
View File

@ -8874,8 +8874,13 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
bool writeback = true;
r = kvm_check_emulate_insn(vcpu, emulation_type, insn, insn_len);
if (r != X86EMUL_CONTINUE)
return 1;
if (r != X86EMUL_CONTINUE) {
if (r == X86EMUL_RETRY_INSTR || r == X86EMUL_PROPAGATE_FAULT)
return 1;
WARN_ON_ONCE(r != X86EMUL_UNHANDLEABLE);
return handle_emulation_failure(vcpu, emulation_type);
}
vcpu->arch.l1tf_flush_l1d = true;