Revert "KVM: SVM: Accelerate nested SVM by emulating parts of GIF=0"kvm-82

This reverts commit 037b6e2531d844994cf79bd4190853427c6af2ac (and
7b8052aecd9c533661493d1140cbec0e1ab311d3 as well).  It causes hangs.

Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 0 insertions, 71 deletions

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 6577934fa096..f53be7e736c6 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -78,11 +78,6 @@ static int nested_svm_vmsave(struct vcpu_svm *svm, void *nested_vmcb,
 			     void *arg2, void *opaque);
 static int nested_svm_check_exception(struct vcpu_svm *svm, unsigned nr,
 				      bool has_error_code, u32 error_code);
-static int vmload_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run);
-static int vmsave_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run);
-static int vmrun_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run);
-static int stgi_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run);
-
 
 static inline struct vcpu_svm *to_svm(struct kvm_vcpu *vcpu)
 {
@@ -1496,50 +1491,6 @@ static int nested_svm_exit_handled(struct vcpu_svm *svm, bool kvm_override)
 			     nested_svm_exit_handled_real);
 }
 
-static int nested_svm_emulate(struct vcpu_svm *svm, struct kvm_run *kvm_run)
-{
-	int er;
-	u32 opcode = 0;
-	unsigned long rip;
-	unsigned long rip_linear;
-
-	svm->vmcb->save.rax = svm->vcpu.arch.regs[VCPU_REGS_RAX];
-	svm->vmcb->save.rsp = svm->vcpu.arch.regs[VCPU_REGS_RSP];
-	svm->vmcb->save.rip = svm->vcpu.arch.regs[VCPU_REGS_RIP];
-	rip = svm->vcpu.arch.regs[VCPU_REGS_RIP];
-	rip_linear = rip + svm_seg(&svm->vcpu, VCPU_SREG_CS)->base;
-
-	er = emulator_read_std(rip_linear, (void *)&opcode, 3, &svm->vcpu);
-	if (er != X86EMUL_CONTINUE)
-		return er;
-	er = EMULATE_FAIL;
-
-	switch (opcode) {
-		case 0xda010f:
-			vmload_interception(svm, kvm_run);
-			er = EMULATE_DONE;
-			break;
-		case 0xd8010f:
-			vmrun_interception(svm, kvm_run);
-			er = EMULATE_DONE;
-			break;
-		case 0xdb010f:
-			vmsave_interception(svm, kvm_run);
-			er = EMULATE_DONE;
-			break;
-		case 0xdc010f:
-			stgi_interception(svm, kvm_run);
-			er = EMULATE_DONE;
-			break;
-		default:
-			nsvm_printk("NSVM: Opcode %x unknown\n", opcode);
-	}
-
-	nsvm_printk("NSVM: svm emul at 0x%lx -> %d\n", rip, er);
-
-	return er;
-}
-
 static int nested_svm_vmexit_real(struct vcpu_svm *svm, void *arg1,
 				  void *arg2, void *opaque)
 {
@@ -1635,9 +1586,6 @@ static int nested_svm_vmexit(struct vcpu_svm *svm)
 	kvm_mmu_reset_context(&svm->vcpu);
 	kvm_mmu_load(&svm->vcpu);
 
-	/* KVM calls vmsave after vmrun, so let's run it now if we can */
-	nested_svm_emulate(svm, NULL);
-
 	return 0;
 }
 
@@ -1848,8 +1796,6 @@ static int stgi_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
 
 static int clgi_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
 {
-	int loopcount = 0;
-
 	if (nested_svm_check_permissions(svm))
 		return 1;
 
@@ -1862,23 +1808,6 @@ static int clgi_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
 	svm_clear_vintr(svm);
 	svm->vmcb->control.int_ctl &= ~V_IRQ_MASK;
 
-	/* Let's try to emulate as many instructions as possible in GIF=0 */
-
-	while (++loopcount < 100) {
-		int er;
-
-		er = emulate_instruction(&svm->vcpu, kvm_run, 0, 0, 0);
-		nsvm_printk("NSVM: emulating at 0x%lx -> %d\n", svm->vcpu.arch.regs[VCPU_REGS_RIP], er);
-
-		/* So we can now emulate the SVM instructions that most probably
-		   occur at the end of the codepath */
-		if (er != EMULATE_DONE) {
-			while (true)
-				if (nested_svm_emulate(svm, kvm_run) == EMULATE_FAIL)
-					break;
-			break;
-		}
-	}
 	return 1;
 }