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Subject[PATCH] KVM: SVM: Add a dedicated INVD intercept routine
Date
From: Tom Lendacky <thomas.lendacky@amd.com>

The INVD instruction intercept performs emulation. Emulation can't be done
on an SEV guest because the guest memory is encrypted.

Provide a dedicated intercept routine for the INVD intercept. Within this
intercept routine just skip the instruction for an SEV guest, since it is
emulated as a NOP anyway.

Fixes: 1654efcbc431 ("KVM: SVM: Add KVM_SEV_INIT command")
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
---
arch/x86/kvm/svm/svm.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index c91acabf18d0..332ec4425d89 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -2183,6 +2183,17 @@ static int iret_interception(struct vcpu_svm *svm)
return 1;
}

+static int invd_interception(struct vcpu_svm *svm)
+{
+ /*
+ * Can't do emulation on an SEV guest and INVD is emulated
+ * as a NOP, so just skip the instruction.
+ */
+ return (sev_guest(svm->vcpu.kvm))
+ ? kvm_skip_emulated_instruction(&svm->vcpu)
+ : kvm_emulate_instruction(&svm->vcpu, 0);
+}
+
static int invlpg_interception(struct vcpu_svm *svm)
{
if (!static_cpu_has(X86_FEATURE_DECODEASSISTS))
@@ -2774,7 +2785,7 @@ static int (*const svm_exit_handlers[])(struct vcpu_svm *svm) = {
[SVM_EXIT_RDPMC] = rdpmc_interception,
[SVM_EXIT_CPUID] = cpuid_interception,
[SVM_EXIT_IRET] = iret_interception,
- [SVM_EXIT_INVD] = emulate_on_interception,
+ [SVM_EXIT_INVD] = invd_interception,
[SVM_EXIT_PAUSE] = pause_interception,
[SVM_EXIT_HLT] = halt_interception,
[SVM_EXIT_INVLPG] = invlpg_interception,
--
2.28.0
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