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Commit 3427318f authored by Laurent Vivier's avatar Laurent Vivier Committed by Avi Kivity
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KVM: Call x86_decode_insn() only when needed 



Move emulate_ctxt to kvm_vcpu to keep emulate context when we exit from kvm
module. Call x86_decode_insn() only when needed. Modify x86_emulate_insn() to
not modify the context if it must be re-entered.

Signed-off-by: default avatarLaurent Vivier <Laurent.Vivier@bull.net>
Signed-off-by: default avatarAvi Kivity <avi@qumranet.com>
parent 1be3aa47

drivers/kvm/kvm.h

+7 −1
Original line number Diff line number Diff line
@@ -207,6 +207,8 @@ enum { 
	VCPU_SREG_LDTR,

};



#include "x86_emulate.h"



struct kvm_pio_request {

	unsigned long count;

	int cur_count;
@@ -380,6 +382,10 @@ struct kvm_vcpu { 


	int cpuid_nent;

	struct kvm_cpuid_entry cpuid_entries[KVM_MAX_CPUID_ENTRIES];



	/* emulate context */



	struct x86_emulate_ctxt emulate_ctxt;

};



struct kvm_mem_alias {
@@ -555,7 +561,7 @@ enum emulation_result { 
};



int emulate_instruction(struct kvm_vcpu *vcpu, struct kvm_run *run,

			unsigned long cr2, u16 error_code);

			unsigned long cr2, u16 error_code, int no_decode);

void kvm_report_emulation_failure(struct kvm_vcpu *cvpu, const char *context);

void realmode_lgdt(struct kvm_vcpu *vcpu, u16 size, unsigned long address);

void realmode_lidt(struct kvm_vcpu *vcpu, u16 size, unsigned long address);

drivers/kvm/kvm_main.c

+44 −33
Original line number Diff line number Diff line
@@ -1251,45 +1251,56 @@ struct x86_emulate_ops emulate_ops = { 
int emulate_instruction(struct kvm_vcpu *vcpu,

			struct kvm_run *run,

			unsigned long cr2,

			u16 error_code)

			u16 error_code,

			int no_decode)

{

	struct x86_emulate_ctxt emulate_ctxt;

	int r;

	int cs_db, cs_l;

	int r = 0;



	vcpu->mmio_fault_cr2 = cr2;

	kvm_x86_ops->cache_regs(vcpu);



	vcpu->mmio_is_write = 0;

	vcpu->pio.string = 0;



	if (!no_decode) {

		int cs_db, cs_l;

		kvm_x86_ops->get_cs_db_l_bits(vcpu, &cs_db, &cs_l);



	emulate_ctxt.vcpu = vcpu;

	emulate_ctxt.eflags = kvm_x86_ops->get_rflags(vcpu);

	emulate_ctxt.cr2 = cr2;

	emulate_ctxt.mode = (emulate_ctxt.eflags & X86_EFLAGS_VM)

		vcpu->emulate_ctxt.vcpu = vcpu;

		vcpu->emulate_ctxt.eflags = kvm_x86_ops->get_rflags(vcpu);

		vcpu->emulate_ctxt.cr2 = cr2;

		vcpu->emulate_ctxt.mode =

			(vcpu->emulate_ctxt.eflags & X86_EFLAGS_VM)

			? X86EMUL_MODE_REAL : cs_l

			? X86EMUL_MODE_PROT64 :	cs_db

			? X86EMUL_MODE_PROT32 : X86EMUL_MODE_PROT16;



	if (emulate_ctxt.mode == X86EMUL_MODE_PROT64) {

		emulate_ctxt.cs_base = 0;

		emulate_ctxt.ds_base = 0;

		emulate_ctxt.es_base = 0;

		emulate_ctxt.ss_base = 0;

		if (vcpu->emulate_ctxt.mode == X86EMUL_MODE_PROT64) {

			vcpu->emulate_ctxt.cs_base = 0;

			vcpu->emulate_ctxt.ds_base = 0;

			vcpu->emulate_ctxt.es_base = 0;

			vcpu->emulate_ctxt.ss_base = 0;

		} else {

		emulate_ctxt.cs_base = get_segment_base(vcpu, VCPU_SREG_CS);

		emulate_ctxt.ds_base = get_segment_base(vcpu, VCPU_SREG_DS);

		emulate_ctxt.es_base = get_segment_base(vcpu, VCPU_SREG_ES);

		emulate_ctxt.ss_base = get_segment_base(vcpu, VCPU_SREG_SS);

			vcpu->emulate_ctxt.cs_base =

					get_segment_base(vcpu, VCPU_SREG_CS);

			vcpu->emulate_ctxt.ds_base =

					get_segment_base(vcpu, VCPU_SREG_DS);

			vcpu->emulate_ctxt.es_base =

					get_segment_base(vcpu, VCPU_SREG_ES);

			vcpu->emulate_ctxt.ss_base =

					get_segment_base(vcpu, VCPU_SREG_SS);

		}



	emulate_ctxt.gs_base = get_segment_base(vcpu, VCPU_SREG_GS);

	emulate_ctxt.fs_base = get_segment_base(vcpu, VCPU_SREG_FS);

		vcpu->emulate_ctxt.gs_base =

					get_segment_base(vcpu, VCPU_SREG_GS);

		vcpu->emulate_ctxt.fs_base =

					get_segment_base(vcpu, VCPU_SREG_FS);



		r = x86_decode_insn(&vcpu->emulate_ctxt, &emulate_ops);

	}



	vcpu->mmio_is_write = 0;

	vcpu->pio.string = 0;

	r = x86_decode_insn(&emulate_ctxt, &emulate_ops);

	if (r == 0)

		r = x86_emulate_insn(&emulate_ctxt, &emulate_ops);

		r = x86_emulate_insn(&vcpu->emulate_ctxt, &emulate_ops);



	if (vcpu->pio.string)

		return EMULATE_DO_MMIO;
@@ -1313,7 +1324,7 @@ int emulate_instruction(struct kvm_vcpu *vcpu, 
	}



	kvm_x86_ops->decache_regs(vcpu);

	kvm_x86_ops->set_rflags(vcpu, emulate_ctxt.eflags);

	kvm_x86_ops->set_rflags(vcpu, vcpu->emulate_ctxt.eflags);



	if (vcpu->mmio_is_write) {

		vcpu->mmio_needed = 0;
@@ -2055,7 +2066,7 @@ static int kvm_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) 
		vcpu->mmio_read_completed = 1;

		vcpu->mmio_needed = 0;

		r = emulate_instruction(vcpu, kvm_run,

					vcpu->mmio_fault_cr2, 0);

					vcpu->mmio_fault_cr2, 0, 1);

		if (r == EMULATE_DO_MMIO) {

			/*

			 * Read-modify-write.  Back to userspace.

drivers/kvm/svm.c

+5 −4
Original line number Diff line number Diff line
@@ -960,7 +960,7 @@ static int pf_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run) 
		return 1;

	}

	er = emulate_instruction(&svm->vcpu, kvm_run, fault_address,

				 error_code);

				 error_code, 0);

	mutex_unlock(&kvm->lock);



	switch (er) {
@@ -984,7 +984,7 @@ static int ud_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run) 
{

	int er;



	er = emulate_instruction(&svm->vcpu, kvm_run, 0, 0);

	er = emulate_instruction(&svm->vcpu, kvm_run, 0, 0, 0);

	if (er != EMULATE_DONE)

		inject_ud(&svm->vcpu);
@@ -1027,7 +1027,8 @@ static int io_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run) 
	string = (io_info & SVM_IOIO_STR_MASK) != 0;



	if (string) {

		if (emulate_instruction(&svm->vcpu, kvm_run, 0, 0) == EMULATE_DO_MMIO)

		if (emulate_instruction(&svm->vcpu,

					kvm_run, 0, 0, 0) == EMULATE_DO_MMIO)

			return 0;

		return 1;

	}
@@ -1086,7 +1087,7 @@ static int cpuid_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run) 
static int emulate_on_interception(struct vcpu_svm *svm,

				   struct kvm_run *kvm_run)

{

	if (emulate_instruction(&svm->vcpu, NULL, 0, 0) != EMULATE_DONE)

	if (emulate_instruction(&svm->vcpu, NULL, 0, 0, 0) != EMULATE_DONE)

		pr_unimpl(&svm->vcpu, "%s: failed\n", __FUNCTION__);

	return 1;

}

drivers/kvm/vmx.c

+5 −4
Original line number Diff line number Diff line
@@ -1750,7 +1750,7 @@ static int handle_rmode_exception(struct kvm_vcpu *vcpu, 
	 * Cause the #SS fault with 0 error code in VM86 mode.

	 */

	if (((vec == GP_VECTOR) || (vec == SS_VECTOR)) && err_code == 0)

		if (emulate_instruction(vcpu, NULL, 0, 0) == EMULATE_DONE)

		if (emulate_instruction(vcpu, NULL, 0, 0, 0) == EMULATE_DONE)

			return 1;

	return 0;

}
@@ -1787,7 +1787,7 @@ static int handle_exception(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) 
	}



	if (is_invalid_opcode(intr_info)) {

		er = emulate_instruction(vcpu, kvm_run, 0, 0);

		er = emulate_instruction(vcpu, kvm_run, 0, 0, 0);

		if (er != EMULATE_DONE)

			vmx_inject_ud(vcpu);
@@ -1812,7 +1812,7 @@ static int handle_exception(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) 
			return 1;

		}



		er = emulate_instruction(vcpu, kvm_run, cr2, error_code);

		er = emulate_instruction(vcpu, kvm_run, cr2, error_code, 0);

		mutex_unlock(&vcpu->kvm->lock);



		switch (er) {
@@ -1873,7 +1873,8 @@ static int handle_io(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) 
	string = (exit_qualification & 16) != 0;



	if (string) {

		if (emulate_instruction(vcpu, kvm_run, 0, 0) == EMULATE_DO_MMIO)

		if (emulate_instruction(vcpu,

					kvm_run, 0, 0, 0) == EMULATE_DO_MMIO)

			return 0;

		return 1;

	}

drivers/kvm/x86_emulate.c

+21 −3
Original line number Diff line number Diff line
@@ -913,10 +913,19 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops) 
	unsigned long cr2 = ctxt->cr2;

	int no_wb = 0;

	u64 msr_data;

	unsigned long saved_eip = 0;

	unsigned long _eflags = ctxt->eflags;

	struct decode_cache *c = &ctxt->decode;

	int rc = 0;



	/* Shadow copy of register state. Committed on successful emulation.

	 * NOTE: we can copy them from vcpu as x86_decode_insn() doesn't

	 * modify them.

	 */



	memcpy(c->regs, ctxt->vcpu->regs, sizeof c->regs);

	saved_eip = c->eip;



	if ((c->d & ModRM) && (c->modrm_mod != 3))

		cr2 = c->modrm_ea;
@@ -1250,7 +1259,11 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops) 
	ctxt->vcpu->rip = c->eip;



done:

	return (rc == X86EMUL_UNHANDLEABLE) ? -1 : 0;

	if (rc == X86EMUL_UNHANDLEABLE) {

		c->eip = saved_eip;

		return -1;

	}

	return 0;



special_insn:

	if (c->twobyte)
@@ -1305,8 +1318,10 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops) 
				register_address(ctxt->es_base,

						 c->regs[VCPU_REGS_RDI]),

				c->rep_prefix,

				c->regs[VCPU_REGS_RDX]) == 0)

				c->regs[VCPU_REGS_RDX]) == 0) {

			c->eip = saved_eip;

			return -1;

		}

		return 0;

	case 0x6e:		/* outsb */

	case 0x6f:		/* outsw/outsd */
@@ -1321,8 +1336,10 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops) 
							ctxt->ds_base,

						 c->regs[VCPU_REGS_RSI]),

				c->rep_prefix,

				c->regs[VCPU_REGS_RDX]) == 0)

				c->regs[VCPU_REGS_RDX]) == 0) {

			c->eip = saved_eip;

			return -1;

		}

		return 0;

	case 0x70 ... 0x7f: /* jcc (short) */ {

		int rel = insn_fetch(s8, 1, c->eip);
@@ -1711,5 +1728,6 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops) 


cannot_emulate:

	DPRINTF("Cannot emulate %02x\n", c->b);

	c->eip = saved_eip;

	return -1;

}