Commit cc440cda authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

KVM: nSVM: implement KVM_GET_NESTED_STATE and KVM_SET_NESTED_STATE 



Similar to VMX, the state that is captured through the currently available
IOCTLs is a mix of L1 and L2 state, dependent on whether the L2 guest was
running at the moment when the process was interrupted to save its state.

In particular, the SVM-specific state for nested virtualization includes
the L1 saved state (including the interrupt flag), the cached L2 controls,
and the GIF.

Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 8ec107c8

arch/x86/include/uapi/asm/kvm.h

+16 −1
Original line number Diff line number Diff line
@@ -385,18 +385,22 @@ struct kvm_sync_regs { 
#define KVM_X86_QUIRK_MISC_ENABLE_NO_MWAIT (1 << 4)



#define KVM_STATE_NESTED_FORMAT_VMX	0

#define KVM_STATE_NESTED_FORMAT_SVM	1	/* unused */

#define KVM_STATE_NESTED_FORMAT_SVM	1



#define KVM_STATE_NESTED_GUEST_MODE	0x00000001

#define KVM_STATE_NESTED_RUN_PENDING	0x00000002

#define KVM_STATE_NESTED_EVMCS		0x00000004

#define KVM_STATE_NESTED_MTF_PENDING	0x00000008

#define KVM_STATE_NESTED_GIF_SET	0x00000100



#define KVM_STATE_NESTED_SMM_GUEST_MODE	0x00000001

#define KVM_STATE_NESTED_SMM_VMXON	0x00000002



#define KVM_STATE_NESTED_VMX_VMCS_SIZE	0x1000



#define KVM_STATE_NESTED_SVM_VMCB_SIZE	0x1000





struct kvm_vmx_nested_state_data {

	__u8 vmcs12[KVM_STATE_NESTED_VMX_VMCS_SIZE];

	__u8 shadow_vmcs12[KVM_STATE_NESTED_VMX_VMCS_SIZE];
@@ -411,6 +415,15 @@ struct kvm_vmx_nested_state_hdr { 
	} smm;

};



struct kvm_svm_nested_state_data {

	/* Save area only used if KVM_STATE_NESTED_RUN_PENDING.  */

	__u8 vmcb12[KVM_STATE_NESTED_SVM_VMCB_SIZE];

};



struct kvm_svm_nested_state_hdr {

	__u64 vmcb_pa;

};



/* for KVM_CAP_NESTED_STATE */

struct kvm_nested_state {

	__u16 flags;
@@ -419,6 +432,7 @@ struct kvm_nested_state { 


	union {

		struct kvm_vmx_nested_state_hdr vmx;

		struct kvm_svm_nested_state_hdr svm;



		/* Pad the header to 128 bytes.  */

		__u8 pad[120];
@@ -431,6 +445,7 @@ struct kvm_nested_state { 
	 */

	union {

		struct kvm_vmx_nested_state_data vmx[0];

		struct kvm_svm_nested_state_data svm[0];

	} data;

};

arch/x86/kvm/cpuid.h

+5 −0
Original line number Diff line number Diff line
@@ -303,4 +303,9 @@ static __always_inline void kvm_cpu_cap_check_and_set(unsigned int x86_feature) 
		kvm_cpu_cap_set(x86_feature);

}



static inline bool page_address_valid(struct kvm_vcpu *vcpu, gpa_t gpa)

{

	return PAGE_ALIGNED(gpa) && !(gpa >> cpuid_maxphyaddr(vcpu));

}



#endif

arch/x86/kvm/svm/nested.c

+147 −0
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ 
#include "trace.h"

#include "mmu.h"

#include "x86.h"

#include "cpuid.h"

#include "lapic.h"

#include "svm.h"
@@ -238,6 +239,8 @@ static void load_nested_vmcb_control(struct vcpu_svm *svm, 
{

	copy_vmcb_control_area(&svm->nested.ctl, control);



	/* Copy it here because nested_svm_check_controls will check it.  */

	svm->nested.ctl.asid           = control->asid;

	svm->nested.ctl.msrpm_base_pa &= ~0x0fffULL;

	svm->nested.ctl.iopm_base_pa  &= ~0x0fffULL;

}
@@ -930,6 +933,150 @@ int nested_svm_exit_special(struct vcpu_svm *svm) 
	return NESTED_EXIT_CONTINUE;

}



static int svm_get_nested_state(struct kvm_vcpu *vcpu,

				struct kvm_nested_state __user *user_kvm_nested_state,

				u32 user_data_size)

{

	struct vcpu_svm *svm;

	struct kvm_nested_state kvm_state = {

		.flags = 0,

		.format = KVM_STATE_NESTED_FORMAT_SVM,

		.size = sizeof(kvm_state),

	};

	struct vmcb __user *user_vmcb = (struct vmcb __user *)

		&user_kvm_nested_state->data.svm[0];



	if (!vcpu)

		return kvm_state.size + KVM_STATE_NESTED_SVM_VMCB_SIZE;



	svm = to_svm(vcpu);



	if (user_data_size < kvm_state.size)

		goto out;



	/* First fill in the header and copy it out.  */

	if (is_guest_mode(vcpu)) {

		kvm_state.hdr.svm.vmcb_pa = svm->nested.vmcb;

		kvm_state.size += KVM_STATE_NESTED_SVM_VMCB_SIZE;

		kvm_state.flags |= KVM_STATE_NESTED_GUEST_MODE;



		if (svm->nested.nested_run_pending)

			kvm_state.flags |= KVM_STATE_NESTED_RUN_PENDING;

	}



	if (gif_set(svm))

		kvm_state.flags |= KVM_STATE_NESTED_GIF_SET;



	if (copy_to_user(user_kvm_nested_state, &kvm_state, sizeof(kvm_state)))

		return -EFAULT;



	if (!is_guest_mode(vcpu))

		goto out;



	/*

	 * Copy over the full size of the VMCB rather than just the size

	 * of the structs.

	 */

	if (clear_user(user_vmcb, KVM_STATE_NESTED_SVM_VMCB_SIZE))

		return -EFAULT;

	if (copy_to_user(&user_vmcb->control, &svm->nested.ctl,

			 sizeof(user_vmcb->control)))

		return -EFAULT;

	if (copy_to_user(&user_vmcb->save, &svm->nested.hsave->save,

			 sizeof(user_vmcb->save)))

		return -EFAULT;



out:

	return kvm_state.size;

}



static int svm_set_nested_state(struct kvm_vcpu *vcpu,

				struct kvm_nested_state __user *user_kvm_nested_state,

				struct kvm_nested_state *kvm_state)

{

	struct vcpu_svm *svm = to_svm(vcpu);

	struct vmcb *hsave = svm->nested.hsave;

	struct vmcb __user *user_vmcb = (struct vmcb __user *)

		&user_kvm_nested_state->data.svm[0];

	struct vmcb_control_area ctl;

	struct vmcb_save_area save;

	u32 cr0;



	if (kvm_state->format != KVM_STATE_NESTED_FORMAT_SVM)

		return -EINVAL;



	if (kvm_state->flags & ~(KVM_STATE_NESTED_GUEST_MODE |

				 KVM_STATE_NESTED_RUN_PENDING |

				 KVM_STATE_NESTED_GIF_SET))

		return -EINVAL;



	/*

	 * If in guest mode, vcpu->arch.efer actually refers to the L2 guest's

	 * EFER.SVME, but EFER.SVME still has to be 1 for VMRUN to succeed.

	 */

	if (!(vcpu->arch.efer & EFER_SVME)) {

		/* GIF=1 and no guest mode are required if SVME=0.  */

		if (kvm_state->flags != KVM_STATE_NESTED_GIF_SET)

			return -EINVAL;

	}



	/* SMM temporarily disables SVM, so we cannot be in guest mode.  */

	if (is_smm(vcpu) && (kvm_state->flags & KVM_STATE_NESTED_GUEST_MODE))

		return -EINVAL;



	if (!(kvm_state->flags & KVM_STATE_NESTED_GUEST_MODE)) {

		svm_leave_nested(svm);

		goto out_set_gif;

	}



	if (!page_address_valid(vcpu, kvm_state->hdr.svm.vmcb_pa))

		return -EINVAL;

	if (kvm_state->size < sizeof(*kvm_state) + KVM_STATE_NESTED_SVM_VMCB_SIZE)

		return -EINVAL;

	if (copy_from_user(&ctl, &user_vmcb->control, sizeof(ctl)))

		return -EFAULT;

	if (copy_from_user(&save, &user_vmcb->save, sizeof(save)))

		return -EFAULT;



	if (!nested_vmcb_check_controls(&ctl))

		return -EINVAL;



	/*

	 * Processor state contains L2 state.  Check that it is

	 * valid for guest mode (see nested_vmcb_checks).

	 */

	cr0 = kvm_read_cr0(vcpu);

        if (((cr0 & X86_CR0_CD) == 0) && (cr0 & X86_CR0_NW))

                return -EINVAL;



	/*

	 * Validate host state saved from before VMRUN (see

	 * nested_svm_check_permissions).

	 * TODO: validate reserved bits for all saved state.

	 */

	if (!(save.cr0 & X86_CR0_PG))

		return -EINVAL;



	/*

	 * All checks done, we can enter guest mode.  L1 control fields

	 * come from the nested save state.  Guest state is already

	 * in the registers, the save area of the nested state instead

	 * contains saved L1 state.

	 */

	copy_vmcb_control_area(&hsave->control, &svm->vmcb->control);

	hsave->save = save;



	svm->nested.vmcb = kvm_state->hdr.svm.vmcb_pa;

	load_nested_vmcb_control(svm, &ctl);

	nested_prepare_vmcb_control(svm);



out_set_gif:

	svm_set_gif(svm, !!(kvm_state->flags & KVM_STATE_NESTED_GIF_SET));

	return 0;

}



struct kvm_x86_nested_ops svm_nested_ops = {

	.check_events = svm_check_nested_events,

	.get_state = svm_get_nested_state,

	.set_state = svm_set_nested_state,

};

arch/x86/kvm/svm/svm.c

+1 −0
Original line number Diff line number Diff line
@@ -1193,6 +1193,7 @@ static int svm_create_vcpu(struct kvm_vcpu *vcpu) 
		svm->avic_is_running = true;



	svm->nested.hsave = page_address(hsave_page);

	clear_page(svm->nested.hsave);



	svm->msrpm = page_address(msrpm_pages);

	svm_vcpu_init_msrpm(svm->msrpm);

arch/x86/kvm/vmx/nested.c

+0 −5
Original line number Diff line number Diff line
@@ -437,11 +437,6 @@ static void vmx_inject_page_fault_nested(struct kvm_vcpu *vcpu, 
	}

}



static bool page_address_valid(struct kvm_vcpu *vcpu, gpa_t gpa)

{

	return PAGE_ALIGNED(gpa) && !(gpa >> cpuid_maxphyaddr(vcpu));

}



static int nested_vmx_check_io_bitmap_controls(struct kvm_vcpu *vcpu,

					       struct vmcs12 *vmcs12)

{