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Commit 35be0ade authored by Sean Christopherson's avatar Sean Christopherson Committed by Radim Krčmář
Browse files

KVM: x86: SVM: Set EMULTYPE_NO_REEXECUTE for RSM emulation 



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: 7607b717 ("KVM: SVM: install RSM intercept")
Cc: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: default avatarSean Christopherson <sean.j.christopherson@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarRadim Krčmář <rkrcmar@redhat.com>
parent c4409905

arch/x86/include/asm/kvm_host.h

+7 −0
Original line number Original line Diff line number Diff line
@@ -1251,6 +1251,13 @@ static inline int emulate_instruction(struct kvm_vcpu *vcpu, 
			emulation_type | EMULTYPE_NO_REEXECUTE, NULL, 0);

			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);

void kvm_enable_efer_bits(u64);

bool kvm_valid_efer(struct kvm_vcpu *vcpu, u64 efer);

bool kvm_valid_efer(struct kvm_vcpu *vcpu, u64 efer);

int kvm_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr);

int kvm_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr);

arch/x86/kvm/svm.c

+2 −2
Original line number Original line Diff line number Diff line
@@ -3874,7 +3874,7 @@ static int emulate_on_interception(struct vcpu_svm *svm) 




static int rsm_interception(struct vcpu_svm *svm)

static int rsm_interception(struct vcpu_svm *svm)

{

{

	return x86_emulate_instruction(&svm->vcpu, 0, 0,

	return kvm_emulate_instruction_from_buffer(&svm->vcpu,

					rsm_ins_bytes, 2) == EMULATE_DONE;

					rsm_ins_bytes, 2) == EMULATE_DONE;

}

}