Commit cf74a78b authored by Alexander Graf's avatar Alexander Graf Committed by Avi Kivity
Browse files

KVM: SVM: Add VMEXIT handler and intercepts 



This adds the #VMEXIT intercept, so we return to the level 1 guest
when something happens in the level 2 guest that should return to
the level 1 guest.

v2 implements HIF handling and cleans up exception interception
v3 adds support for V_INTR_MASKING_MASK
v4 uses the host page hsave
v5 removes IOPM merging code
v6 moves mmu code out of the atomic section

Acked-by: default avatarJoerg Roedel <joro@8bytes.org>
Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent 3d6368ef

arch/x86/kvm/svm.c

+293 −0
Original line number Diff line number Diff line
@@ -72,6 +72,13 @@ module_param(npt, int, S_IRUGO); 
static void kvm_reput_irq(struct vcpu_svm *svm);

static void svm_flush_tlb(struct kvm_vcpu *vcpu);



static int nested_svm_exit_handled(struct vcpu_svm *svm, bool kvm_override);

static int nested_svm_vmexit(struct vcpu_svm *svm);

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 inline struct vcpu_svm *to_svm(struct kvm_vcpu *vcpu)

{

	return container_of(vcpu, struct vcpu_svm, vcpu);
@@ -221,6 +228,11 @@ static void svm_queue_exception(struct kvm_vcpu *vcpu, unsigned nr, 
{

	struct vcpu_svm *svm = to_svm(vcpu);



	/* If we are within a nested VM we'd better #VMEXIT and let the

	   guest handle the exception */

	if (nested_svm_check_exception(svm, nr, has_error_code, error_code))

		return;



	svm->vmcb->control.event_inj = nr

		| SVM_EVTINJ_VALID

		| (has_error_code ? SVM_EVTINJ_VALID_ERR : 0)
@@ -1198,6 +1210,46 @@ static int nested_svm_check_permissions(struct vcpu_svm *svm) 
       return 0;

}



static int nested_svm_check_exception(struct vcpu_svm *svm, unsigned nr,

				      bool has_error_code, u32 error_code)

{

	if (is_nested(svm)) {

		svm->vmcb->control.exit_code = SVM_EXIT_EXCP_BASE + nr;

		svm->vmcb->control.exit_code_hi = 0;

		svm->vmcb->control.exit_info_1 = error_code;

		svm->vmcb->control.exit_info_2 = svm->vcpu.arch.cr2;

		if (nested_svm_exit_handled(svm, false)) {

			nsvm_printk("VMexit -> EXCP 0x%x\n", nr);



			nested_svm_vmexit(svm);

			return 1;

		}

	}



	return 0;

}



static inline int nested_svm_intr(struct vcpu_svm *svm)

{

	if (is_nested(svm)) {

		if (!(svm->vcpu.arch.hflags & HF_VINTR_MASK))

			return 0;



		if (!(svm->vcpu.arch.hflags & HF_HIF_MASK))

			return 0;



		svm->vmcb->control.exit_code = SVM_EXIT_INTR;



		if (nested_svm_exit_handled(svm, false)) {

			nsvm_printk("VMexit -> INTR\n");

			nested_svm_vmexit(svm);

			return 1;

		}

	}



	return 0;

}



static struct page *nested_svm_get_page(struct vcpu_svm *svm, u64 gpa)

{

	struct page *page;
@@ -1258,6 +1310,228 @@ static int nested_svm_do(struct vcpu_svm *svm, 
	return retval;

}



static int nested_svm_exit_handled_real(struct vcpu_svm *svm,

					void *arg1,

					void *arg2,

					void *opaque)

{

	struct vmcb *nested_vmcb = (struct vmcb *)arg1;

	bool kvm_overrides = *(bool *)opaque;

	u32 exit_code = svm->vmcb->control.exit_code;



	if (kvm_overrides) {

		switch (exit_code) {

		case SVM_EXIT_INTR:

		case SVM_EXIT_NMI:

			return 0;

		/* For now we are always handling NPFs when using them */

		case SVM_EXIT_NPF:

			if (npt_enabled)

				return 0;

			break;

		/* When we're shadowing, trap PFs */

		case SVM_EXIT_EXCP_BASE + PF_VECTOR:

			if (!npt_enabled)

				return 0;

			break;

		default:

			break;

		}

	}



	switch (exit_code) {

	case SVM_EXIT_READ_CR0 ... SVM_EXIT_READ_CR8: {

		u32 cr_bits = 1 << (exit_code - SVM_EXIT_READ_CR0);

		if (nested_vmcb->control.intercept_cr_read & cr_bits)

			return 1;

		break;

	}

	case SVM_EXIT_WRITE_CR0 ... SVM_EXIT_WRITE_CR8: {

		u32 cr_bits = 1 << (exit_code - SVM_EXIT_WRITE_CR0);

		if (nested_vmcb->control.intercept_cr_write & cr_bits)

			return 1;

		break;

	}

	case SVM_EXIT_READ_DR0 ... SVM_EXIT_READ_DR7: {

		u32 dr_bits = 1 << (exit_code - SVM_EXIT_READ_DR0);

		if (nested_vmcb->control.intercept_dr_read & dr_bits)

			return 1;

		break;

	}

	case SVM_EXIT_WRITE_DR0 ... SVM_EXIT_WRITE_DR7: {

		u32 dr_bits = 1 << (exit_code - SVM_EXIT_WRITE_DR0);

		if (nested_vmcb->control.intercept_dr_write & dr_bits)

			return 1;

		break;

	}

	case SVM_EXIT_EXCP_BASE ... SVM_EXIT_EXCP_BASE + 0x1f: {

		u32 excp_bits = 1 << (exit_code - SVM_EXIT_EXCP_BASE);

		if (nested_vmcb->control.intercept_exceptions & excp_bits)

			return 1;

		break;

	}

	default: {

		u64 exit_bits = 1ULL << (exit_code - SVM_EXIT_INTR);

		nsvm_printk("exit code: 0x%x\n", exit_code);

		if (nested_vmcb->control.intercept & exit_bits)

			return 1;

	}

	}



	return 0;

}



static int nested_svm_exit_handled_msr(struct vcpu_svm *svm,

				       void *arg1, void *arg2,

				       void *opaque)

{

	struct vmcb *nested_vmcb = (struct vmcb *)arg1;

	u8 *msrpm = (u8 *)arg2;

        u32 t0, t1;

	u32 msr = svm->vcpu.arch.regs[VCPU_REGS_RCX];

	u32 param = svm->vmcb->control.exit_info_1 & 1;



	if (!(nested_vmcb->control.intercept & (1ULL << INTERCEPT_MSR_PROT)))

		return 0;



	switch(msr) {

	case 0 ... 0x1fff:

		t0 = (msr * 2) % 8;

		t1 = msr / 8;

		break;

	case 0xc0000000 ... 0xc0001fff:

		t0 = (8192 + msr - 0xc0000000) * 2;

		t1 = (t0 / 8);

		t0 %= 8;

		break;

	case 0xc0010000 ... 0xc0011fff:

		t0 = (16384 + msr - 0xc0010000) * 2;

		t1 = (t0 / 8);

		t0 %= 8;

		break;

	default:

		return 1;

		break;

	}

	if (msrpm[t1] & ((1 << param) << t0))

		return 1;



	return 0;

}



static int nested_svm_exit_handled(struct vcpu_svm *svm, bool kvm_override)

{

	bool k = kvm_override;



	switch (svm->vmcb->control.exit_code) {

	case SVM_EXIT_MSR:

		return nested_svm_do(svm, svm->nested_vmcb,

				     svm->nested_vmcb_msrpm, NULL,

				     nested_svm_exit_handled_msr);

	default: break;

	}



	return nested_svm_do(svm, svm->nested_vmcb, 0, &k,

			     nested_svm_exit_handled_real);

}



static int nested_svm_vmexit_real(struct vcpu_svm *svm, void *arg1,

				  void *arg2, void *opaque)

{

	struct vmcb *nested_vmcb = (struct vmcb *)arg1;

	struct vmcb *hsave = svm->hsave;

	u64 nested_save[] = { nested_vmcb->save.cr0,

			      nested_vmcb->save.cr3,

			      nested_vmcb->save.cr4,

			      nested_vmcb->save.efer,

			      nested_vmcb->control.intercept_cr_read,

			      nested_vmcb->control.intercept_cr_write,

			      nested_vmcb->control.intercept_dr_read,

			      nested_vmcb->control.intercept_dr_write,

			      nested_vmcb->control.intercept_exceptions,

			      nested_vmcb->control.intercept,

			      nested_vmcb->control.msrpm_base_pa,

			      nested_vmcb->control.iopm_base_pa,

			      nested_vmcb->control.tsc_offset };



	/* Give the current vmcb to the guest */

	memcpy(nested_vmcb, svm->vmcb, sizeof(struct vmcb));

	nested_vmcb->save.cr0 = nested_save[0];

	if (!npt_enabled)

		nested_vmcb->save.cr3 = nested_save[1];

	nested_vmcb->save.cr4 = nested_save[2];

	nested_vmcb->save.efer = nested_save[3];

	nested_vmcb->control.intercept_cr_read = nested_save[4];

	nested_vmcb->control.intercept_cr_write = nested_save[5];

	nested_vmcb->control.intercept_dr_read = nested_save[6];

	nested_vmcb->control.intercept_dr_write = nested_save[7];

	nested_vmcb->control.intercept_exceptions = nested_save[8];

	nested_vmcb->control.intercept = nested_save[9];

	nested_vmcb->control.msrpm_base_pa = nested_save[10];

	nested_vmcb->control.iopm_base_pa = nested_save[11];

	nested_vmcb->control.tsc_offset = nested_save[12];



	/* We always set V_INTR_MASKING and remember the old value in hflags */

	if (!(svm->vcpu.arch.hflags & HF_VINTR_MASK))

		nested_vmcb->control.int_ctl &= ~V_INTR_MASKING_MASK;



	if ((nested_vmcb->control.int_ctl & V_IRQ_MASK) &&

	    (nested_vmcb->control.int_vector)) {

		nsvm_printk("WARNING: IRQ 0x%x still enabled on #VMEXIT\n",

				nested_vmcb->control.int_vector);

	}



	/* Restore the original control entries */

	svm->vmcb->control = hsave->control;



	/* Kill any pending exceptions */

	if (svm->vcpu.arch.exception.pending == true)

		nsvm_printk("WARNING: Pending Exception\n");

	svm->vcpu.arch.exception.pending = false;



	/* Restore selected save entries */

	svm->vmcb->save.es = hsave->save.es;

	svm->vmcb->save.cs = hsave->save.cs;

	svm->vmcb->save.ss = hsave->save.ss;

	svm->vmcb->save.ds = hsave->save.ds;

	svm->vmcb->save.gdtr = hsave->save.gdtr;

	svm->vmcb->save.idtr = hsave->save.idtr;

	svm->vmcb->save.rflags = hsave->save.rflags;

	svm_set_efer(&svm->vcpu, hsave->save.efer);

	svm_set_cr0(&svm->vcpu, hsave->save.cr0 | X86_CR0_PE);

	svm_set_cr4(&svm->vcpu, hsave->save.cr4);

	if (npt_enabled) {

		svm->vmcb->save.cr3 = hsave->save.cr3;

		svm->vcpu.arch.cr3 = hsave->save.cr3;

	} else {

		kvm_set_cr3(&svm->vcpu, hsave->save.cr3);

	}

	kvm_register_write(&svm->vcpu, VCPU_REGS_RAX, hsave->save.rax);

	kvm_register_write(&svm->vcpu, VCPU_REGS_RSP, hsave->save.rsp);

	kvm_register_write(&svm->vcpu, VCPU_REGS_RIP, hsave->save.rip);

	svm->vmcb->save.dr7 = 0;

	svm->vmcb->save.cpl = 0;

	svm->vmcb->control.exit_int_info = 0;



	svm->vcpu.arch.hflags &= ~HF_GIF_MASK;

	/* Exit nested SVM mode */

	svm->nested_vmcb = 0;



	return 0;

}



static int nested_svm_vmexit(struct vcpu_svm *svm)

{

	nsvm_printk("VMexit\n");

	if (nested_svm_do(svm, svm->nested_vmcb, 0,

			  NULL, nested_svm_vmexit_real))

		return 1;



	kvm_mmu_reset_context(&svm->vcpu);

	kvm_mmu_load(&svm->vcpu);



	return 0;

}



static int nested_svm_vmrun_msrpm(struct vcpu_svm *svm, void *arg1,

				  void *arg2, void *opaque)
@@ -1805,6 +2079,17 @@ static int handle_exit(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu) 
	KVMTRACE_3D(VMEXIT, vcpu, exit_code, (u32)svm->vmcb->save.rip,

		    (u32)((u64)svm->vmcb->save.rip >> 32), entryexit);



	if (is_nested(svm)) {

		nsvm_printk("nested handle_exit: 0x%x | 0x%lx | 0x%lx | 0x%lx\n",

			    exit_code, svm->vmcb->control.exit_info_1,

			    svm->vmcb->control.exit_info_2, svm->vmcb->save.rip);

		if (nested_svm_exit_handled(svm, true)) {

			nested_svm_vmexit(svm);

			nsvm_printk("-> #VMEXIT\n");

			return 1;

		}

	}



	if (npt_enabled) {

		int mmu_reload = 0;

		if ((vcpu->arch.cr0 ^ svm->vmcb->save.cr0) & X86_CR0_PG) {
@@ -1892,6 +2177,8 @@ static void svm_set_irq(struct kvm_vcpu *vcpu, int irq) 
{

	struct vcpu_svm *svm = to_svm(vcpu);



	nested_svm_intr(svm);



	svm_inject_irq(svm, irq);

}
@@ -1937,6 +2224,9 @@ static void svm_intr_assist(struct kvm_vcpu *vcpu) 
	if (!kvm_cpu_has_interrupt(vcpu))

		goto out;



	if (nested_svm_intr(svm))

		goto out;



	if (!(svm->vcpu.arch.hflags & HF_GIF_MASK))

		goto out;
@@ -1989,6 +2279,9 @@ static void do_interrupt_requests(struct kvm_vcpu *vcpu, 
	struct vcpu_svm *svm = to_svm(vcpu);

	struct vmcb_control_area *control = &svm->vmcb->control;



	if (nested_svm_intr(svm))

		return;



	svm->vcpu.arch.interrupt_window_open =

		(!(control->int_state & SVM_INTERRUPT_SHADOW_MASK) &&

		 (svm->vmcb->save.rflags & X86_EFLAGS_IF) &&

CRA Git | Maintained and supported by SUSTech CRA and CCSE