Commit c9ecafaf authored by Vitaly Kuznetsov's avatar Vitaly Kuznetsov Committed by Paolo Bonzini
Browse files

KVM: selftests: evmcs_test: Check that VMCS12 is alway properly synced to eVMCS after restore 



Add a test for the regression, introduced by commit f2c7ef3b
("KVM: nSVM: cancel KVM_REQ_GET_NESTED_STATE_PAGES on nested vmexit"). When
L2->L1 exit is forced immediately after restoring nested state,
KVM_REQ_GET_NESTED_STATE_PAGES request is cleared and VMCS12 changes
(e.g. fresh RIP) are not reflected to eVMCS. The consequent nested
vCPU run gets broken.

Utilize NMI injection to do the job.

Signed-off-by: default avatarVitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20210505151823.1341678-3-vkuznets@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 32d1b3ab

tools/testing/selftests/kvm/x86_64/evmcs_test.c

+55 −11
Original line number Diff line number Diff line
@@ -18,30 +18,52 @@ 
#include "vmx.h"



#define VCPU_ID		5

#define NMI_VECTOR	2



static int ud_count;



void enable_x2apic(void)

{

	uint32_t spiv_reg = APIC_BASE_MSR + (APIC_SPIV >> 4);



	wrmsr(MSR_IA32_APICBASE, rdmsr(MSR_IA32_APICBASE) |

	      MSR_IA32_APICBASE_ENABLE | MSR_IA32_APICBASE_EXTD);

	wrmsr(spiv_reg, rdmsr(spiv_reg) | APIC_SPIV_APIC_ENABLED);

}



static void guest_ud_handler(struct ex_regs *regs)

{

	ud_count++;

	regs->rip += 3; /* VMLAUNCH */

}



static void guest_nmi_handler(struct ex_regs *regs)

{

}



void l2_guest_code(void)

{

	GUEST_SYNC(7);



	GUEST_SYNC(8);



	/* Forced exit to L1 upon restore */

	GUEST_SYNC(9);



	/* Done, exit to L1 and never come back.  */

	vmcall();

}



void l1_guest_code(struct vmx_pages *vmx_pages)

void guest_code(struct vmx_pages *vmx_pages)

{

#define L2_GUEST_STACK_SIZE 64

	unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE];



	enable_x2apic();



	GUEST_SYNC(1);

	GUEST_SYNC(2);



	enable_vp_assist(vmx_pages->vp_assist_gpa, vmx_pages->vp_assist);



	GUEST_ASSERT(vmx_pages->vmcs_gpa);
@@ -63,21 +85,22 @@ void l1_guest_code(struct vmx_pages *vmx_pages) 
	current_evmcs->revision_id = EVMCS_VERSION;

	GUEST_SYNC(6);



	current_evmcs->pin_based_vm_exec_control |=

		PIN_BASED_NMI_EXITING;

	GUEST_ASSERT(!vmlaunch());

	GUEST_ASSERT(vmptrstz() == vmx_pages->enlightened_vmcs_gpa);

	GUEST_SYNC(9);



	/*

	 * NMI forces L2->L1 exit, resuming L2 and hope that EVMCS is

	 * up-to-date (RIP points where it should and not at the beginning

	 * of l2_guest_code(). GUEST_SYNC(9) checkes that.

	 */

	GUEST_ASSERT(!vmresume());

	GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);

	GUEST_SYNC(10);

}



void guest_code(struct vmx_pages *vmx_pages)

{

	GUEST_SYNC(1);

	GUEST_SYNC(2);

	GUEST_SYNC(10);



	if (vmx_pages)

		l1_guest_code(vmx_pages);

	GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);

	GUEST_SYNC(11);



	/* Try enlightened vmptrld with an incorrect GPA */

	evmcs_vmptrld(0xdeadbeef, vmx_pages->enlightened_vmcs);
@@ -86,6 +109,18 @@ void guest_code(struct vmx_pages *vmx_pages) 
	GUEST_DONE();

}



void inject_nmi(struct kvm_vm *vm)

{

	struct kvm_vcpu_events events;



	vcpu_events_get(vm, VCPU_ID, &events);



	events.nmi.pending = 1;

	events.flags |= KVM_VCPUEVENT_VALID_NMI_PENDING;



	vcpu_events_set(vm, VCPU_ID, &events);

}



int main(int argc, char *argv[])

{

	vm_vaddr_t vmx_pages_gva = 0;
@@ -120,6 +155,9 @@ int main(int argc, char *argv[]) 
	vm_init_descriptor_tables(vm);

	vcpu_init_descriptor_tables(vm, VCPU_ID);

	vm_handle_exception(vm, UD_VECTOR, guest_ud_handler);

	vm_handle_exception(vm, NMI_VECTOR, guest_nmi_handler);



	pr_info("Running L1 which uses EVMCS to run L2\n");



	for (stage = 1;; stage++) {

		_vcpu_run(vm, VCPU_ID);
@@ -166,6 +204,12 @@ int main(int argc, char *argv[]) 
		TEST_ASSERT(!memcmp(&regs1, &regs2, sizeof(regs2)),

			    "Unexpected register values after vcpu_load_state; rdi: %lx rsi: %lx",

			    (ulong) regs2.rdi, (ulong) regs2.rsi);



		/* Force immediate L2->L1 exit before resuming */

		if (stage == 8) {

			pr_info("Injecting NMI into L1 before L2 had a chance to run after restore\n");

			inject_nmi(vm);

		}

	}



done: