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Commit dc25e89e authored by Andre Przywara's avatar Andre Przywara Committed by Avi Kivity
Browse files

KVM: SVM: copy instruction bytes from VMCB 



In case of a nested page fault or an intercepted #PF newer SVM
implementations provide a copy of the faulting instruction bytes
in the VMCB.
Use these bytes to feed the instruction emulator and avoid the costly
guest instruction fetch in this case.

Signed-off-by: default avatarAndre Przywara <andre.przywara@amd.com>
Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
parent df4f3108

arch/x86/include/asm/kvm_emulate.h

+1 −1
Original line number Diff line number Diff line
@@ -265,7 +265,7 @@ struct x86_emulate_ctxt { 
#define X86EMUL_MODE_HOST X86EMUL_MODE_PROT64

#endif



int x86_decode_insn(struct x86_emulate_ctxt *ctxt);

int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len);

#define EMULATION_FAILED -1

#define EMULATION_OK 0

#define EMULATION_RESTART 1

arch/x86/include/asm/kvm_host.h

+5 −4
Original line number Diff line number Diff line
@@ -634,13 +634,13 @@ enum emulation_result { 
#define EMULTYPE_NO_DECODE	    (1 << 0)

#define EMULTYPE_TRAP_UD	    (1 << 1)

#define EMULTYPE_SKIP		    (1 << 2)

int x86_emulate_instruction(struct kvm_vcpu *vcpu,

			unsigned long cr2, int emulation_type);

int x86_emulate_instruction(struct kvm_vcpu *vcpu, unsigned long cr2,

			    int emulation_type, void *insn, int insn_len);



static inline int emulate_instruction(struct kvm_vcpu *vcpu,

			int emulation_type)

{

	return x86_emulate_instruction(vcpu, 0, emulation_type);

	return x86_emulate_instruction(vcpu, 0, emulation_type, NULL, 0);

}



void realmode_lgdt(struct kvm_vcpu *vcpu, u16 size, unsigned long address);
@@ -721,7 +721,8 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu); 


int kvm_fix_hypercall(struct kvm_vcpu *vcpu);



int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t gva, u32 error_code);

int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t gva, u32 error_code,

		       void *insn, int insn_len);

void kvm_mmu_invlpg(struct kvm_vcpu *vcpu, gva_t gva);



void kvm_enable_tdp(void);

arch/x86/include/asm/svm.h

+3 −1
Original line number Diff line number Diff line
@@ -83,7 +83,9 @@ struct __attribute__ ((__packed__)) vmcb_control_area { 
	u32 clean;

	u32 reserved_5;

	u64 next_rip;

	u8 reserved_6[816];

	u8 insn_len;

	u8 insn_bytes[15];

	u8 reserved_6[800];

};

arch/x86/kvm/emulate.c

+5 −2
Original line number Diff line number Diff line
@@ -2610,7 +2610,7 @@ static int decode_imm(struct x86_emulate_ctxt *ctxt, struct operand *op, 
}



int

x86_decode_insn(struct x86_emulate_ctxt *ctxt)

x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len)

{

	struct x86_emulate_ops *ops = ctxt->ops;

	struct decode_cache *c = &ctxt->decode;
@@ -2621,7 +2621,10 @@ x86_decode_insn(struct x86_emulate_ctxt *ctxt) 
	struct operand memop = { .type = OP_NONE };



	c->eip = ctxt->eip;

	c->fetch.start = c->fetch.end = c->eip;

	c->fetch.start = c->eip;

	c->fetch.end = c->fetch.start + insn_len;

	if (insn_len > 0)

		memcpy(c->fetch.data, insn, insn_len);

	ctxt->cs_base = seg_base(ctxt, ops, VCPU_SREG_CS);



	switch (mode) {

arch/x86/kvm/mmu.c

+3 −2
Original line number Diff line number Diff line
@@ -3330,7 +3330,8 @@ void __kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu) 
	}

}



int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t cr2, u32 error_code)

int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t cr2, u32 error_code,

		       void *insn, int insn_len)

{

	int r;

	enum emulation_result er;
@@ -3348,7 +3349,7 @@ int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t cr2, u32 error_code) 
	if (r)

		goto out;



	er = x86_emulate_instruction(vcpu, cr2, 0);

	er = x86_emulate_instruction(vcpu, cr2, 0, insn, insn_len);



	switch (er) {

	case EMULATE_DONE: