Commit e269fb21 authored by Jan Kiszka's avatar Jan Kiszka Committed by Avi Kivity
Browse files

KVM: x86: Push potential exception error code on task switches 



When a fault triggers a task switch, the error code, if existent, has to
be pushed on the new task's stack. Implement the missing bits.

Signed-off-by: default avatarJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
parent 0760d448

arch/x86/include/asm/kvm_emulate.h

+2 −1
Original line number Diff line number Diff line
@@ -230,6 +230,7 @@ int x86_emulate_insn(struct x86_emulate_ctxt *ctxt, 
		     struct x86_emulate_ops *ops);

int emulator_task_switch(struct x86_emulate_ctxt *ctxt,

			 struct x86_emulate_ops *ops,

			 u16 tss_selector, int reason);

			 u16 tss_selector, int reason,

			 bool has_error_code, u32 error_code);



#endif /* _ASM_X86_KVM_X86_EMULATE_H */

arch/x86/include/asm/kvm_host.h

+2 −1
Original line number Diff line number Diff line
@@ -595,7 +595,8 @@ int emulator_set_dr(struct x86_emulate_ctxt *ctxt, int dr, 
void kvm_get_segment(struct kvm_vcpu *vcpu, struct kvm_segment *var, int seg);

int kvm_load_segment_descriptor(struct kvm_vcpu *vcpu, u16 selector, int seg);



int kvm_task_switch(struct kvm_vcpu *vcpu, u16 tss_selector, int reason);

int kvm_task_switch(struct kvm_vcpu *vcpu, u16 tss_selector, int reason,

		    bool has_error_code, u32 error_code);



void kvm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0);

void kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3);

arch/x86/include/asm/svm.h

+1 −0
Original line number Diff line number Diff line
@@ -244,6 +244,7 @@ struct __attribute__ ((__packed__)) vmcb { 


#define SVM_EXITINFOSHIFT_TS_REASON_IRET 36

#define SVM_EXITINFOSHIFT_TS_REASON_JMP 38

#define SVM_EXITINFOSHIFT_TS_HAS_ERROR_CODE 44



#define	SVM_EXIT_READ_CR0 	0x000

#define	SVM_EXIT_READ_CR3 	0x003

arch/x86/kvm/emulate.c

+18 −4
Original line number Diff line number Diff line
@@ -2345,7 +2345,8 @@ static int task_switch_32(struct x86_emulate_ctxt *ctxt, 


static int emulator_do_task_switch(struct x86_emulate_ctxt *ctxt,

				   struct x86_emulate_ops *ops,

				    u16 tss_selector, int reason)

				   u16 tss_selector, int reason,

				   bool has_error_code, u32 error_code)

{

	struct desc_struct curr_tss_desc, next_tss_desc;

	int ret;
@@ -2418,12 +2419,22 @@ static int emulator_do_task_switch(struct x86_emulate_ctxt *ctxt, 
	ops->set_cached_descriptor(&next_tss_desc, VCPU_SREG_TR, ctxt->vcpu);

	ops->set_segment_selector(tss_selector, VCPU_SREG_TR, ctxt->vcpu);



	if (has_error_code) {

		struct decode_cache *c = &ctxt->decode;



		c->op_bytes = c->ad_bytes = (next_tss_desc.type & 8) ? 4 : 2;

		c->lock_prefix = 0;

		c->src.val = (unsigned long) error_code;

		emulate_push(ctxt);

	}



	return ret;

}



int emulator_task_switch(struct x86_emulate_ctxt *ctxt,

			 struct x86_emulate_ops *ops,

			 u16 tss_selector, int reason)

			 u16 tss_selector, int reason,

			 bool has_error_code, u32 error_code)

{

	struct decode_cache *c = &ctxt->decode;

	int rc;
@@ -2431,12 +2442,15 @@ int emulator_task_switch(struct x86_emulate_ctxt *ctxt, 
	memset(c, 0, sizeof(struct decode_cache));

	c->eip = ctxt->eip;

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

	c->dst.type = OP_NONE;



	rc = emulator_do_task_switch(ctxt, ops, tss_selector, reason);

	rc = emulator_do_task_switch(ctxt, ops, tss_selector, reason,

				     has_error_code, error_code);



	if (rc == X86EMUL_CONTINUE) {

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

		kvm_rip_write(ctxt->vcpu, c->eip);

		rc = writeback(ctxt, ops);

	}



	return rc;

arch/x86/kvm/svm.c

+10 −1
Original line number Diff line number Diff line
@@ -2222,6 +2222,8 @@ static int task_switch_interception(struct vcpu_svm *svm) 
		svm->vmcb->control.exit_int_info & SVM_EXITINTINFO_TYPE_MASK;

	uint32_t idt_v =

		svm->vmcb->control.exit_int_info & SVM_EXITINTINFO_VALID;

	bool has_error_code = false;

	u32 error_code = 0;



	tss_selector = (u16)svm->vmcb->control.exit_info_1;
@@ -2242,6 +2244,12 @@ static int task_switch_interception(struct vcpu_svm *svm) 
			svm->vcpu.arch.nmi_injected = false;

			break;

		case SVM_EXITINTINFO_TYPE_EXEPT:

			if (svm->vmcb->control.exit_info_2 &

			    (1ULL << SVM_EXITINFOSHIFT_TS_HAS_ERROR_CODE)) {

				has_error_code = true;

				error_code =

					(u32)svm->vmcb->control.exit_info_2;

			}

			kvm_clear_exception_queue(&svm->vcpu);

			break;

		case SVM_EXITINTINFO_TYPE_INTR:
@@ -2258,7 +2266,8 @@ static int task_switch_interception(struct vcpu_svm *svm) 
	     (int_vec == OF_VECTOR || int_vec == BP_VECTOR)))

		skip_emulated_instruction(&svm->vcpu);



	return kvm_task_switch(&svm->vcpu, tss_selector, reason);

	return kvm_task_switch(&svm->vcpu, tss_selector, reason,

			       has_error_code, error_code);

}



static int cpuid_interception(struct vcpu_svm *svm)