4.18-stable review patch. If anyone has any objections, please let me know.
------------------
From: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
commit 35be0aded76b54a24dc8aa678a71bca22273e8d8 upstream.
Re-execution after an emulation decode failure is only intended to
handle a case where two or vCPUs race to write a shadowed page, i.e.
we should never re-execute an instruction as part of RSM emulation.
Add a new helper, kvm_emulate_instruction_from_buffer(), to support
emulating from a pre-defined buffer. This eliminates the last direct
call to x86_emulate_instruction() outside of kvm_mmu_page_fault(),
which means x86_emulate_instruction() can be unexported in a future
patch.
Fixes: 7607b7174405 ("KVM: SVM: install RSM intercept")
Cc: Brijesh Singh <brijesh.singh@xxxxxxx>
Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Radim Krčmář <rkrcmar@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/include/asm/kvm_host.h | 7 +++++++
arch/x86/kvm/svm.c | 4 ++--
2 files changed, 9 insertions(+), 2 deletions(-)
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1212,6 +1212,13 @@ static inline int emulate_instruction(st
emulation_type | EMULTYPE_NO_REEXECUTE, NULL, 0);
}
+static inline int kvm_emulate_instruction_from_buffer(struct kvm_vcpu *vcpu,
+ void *insn, int insn_len)
+{
+ return x86_emulate_instruction(vcpu, 0, EMULTYPE_NO_REEXECUTE,
+ insn, insn_len);
+}
+
void kvm_enable_efer_bits(u64);
bool kvm_valid_efer(struct kvm_vcpu *vcpu, u64 efer);
int kvm_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr);
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -3875,8 +3875,8 @@ static int emulate_on_interception(struc
static int rsm_interception(struct vcpu_svm *svm)
{
- return x86_emulate_instruction(&svm->vcpu, 0, 0,
- rsm_ins_bytes, 2) == EMULATE_DONE;
+ return kvm_emulate_instruction_from_buffer(&svm->vcpu,
+ rsm_ins_bytes, 2) == EMULATE_DONE;
}
static int rdpmc_interception(struct vcpu_svm *svm)
