Commit 75ee7505 authored by Vitaly Kuznetsov's avatar Vitaly Kuznetsov Committed by Paolo Bonzini
Browse files

KVM: selftests: Introduce rdmsr_from_l2() and use it for MSR-Bitmap tests 



Hyper-V MSR-Bitmap tests do RDMSR from L2 to exit to L1. While 'evmcs_test'
correctly clobbers all GPRs (which are not preserved), 'hyperv_svm_test'
does not. Introduce a more generic rdmsr_from_l2() to avoid code
duplication and remove hardcoding of MSRs.  Do not put it in common code
because it is really just a selftests bug rather than a processor
feature that requires it.

Signed-off-by: default avatarVitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Message-Id: <20221101145426.251680-46-vkuznets@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 8fda37cf

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

+10 −17
Original line number Diff line number Diff line
@@ -30,22 +30,15 @@ static void guest_nmi_handler(struct ex_regs *regs) 
{

}



/* Exits to L1 destroy GRPs! */

static inline void rdmsr_fs_base(void)

static inline void rdmsr_from_l2(uint32_t msr)

{

	__asm__ __volatile__ ("mov $0xc0000100, %%rcx; rdmsr" : : :

			      "rax", "rbx", "rcx", "rdx",

			      "rsi", "rdi", "r8", "r9", "r10", "r11", "r12",

			      "r13", "r14", "r15");

}

static inline void rdmsr_gs_base(void)

{

	__asm__ __volatile__ ("mov $0xc0000101, %%rcx; rdmsr" : : :

			      "rax", "rbx", "rcx", "rdx",

			      "rsi", "rdi", "r8", "r9", "r10", "r11", "r12",

			      "r13", "r14", "r15");

	/* Currently, L1 doesn't preserve GPRs during vmexits. */

	__asm__ __volatile__ ("rdmsr" : : "c"(msr) :

			      "rax", "rbx", "rdx", "rsi", "rdi", "r8", "r9",

			      "r10", "r11", "r12", "r13", "r14", "r15");

}



/* Exit to L1 from L2 with RDMSR instruction */

void l2_guest_code(void)

{

	GUEST_SYNC(7);
@@ -58,11 +51,11 @@ void l2_guest_code(void) 
	vmcall();



	/* MSR-Bitmap tests */

	rdmsr_fs_base(); /* intercepted */

	rdmsr_fs_base(); /* intercepted */

	rdmsr_gs_base(); /* not intercepted */

	rdmsr_from_l2(MSR_FS_BASE); /* intercepted */

	rdmsr_from_l2(MSR_FS_BASE); /* intercepted */

	rdmsr_from_l2(MSR_GS_BASE); /* not intercepted */

	vmcall();

	rdmsr_gs_base(); /* intercepted */

	rdmsr_from_l2(MSR_GS_BASE); /* intercepted */



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

	vmcall();

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

+13 −4
Original line number Diff line number Diff line
@@ -23,6 +23,15 @@ 


#define L2_GUEST_STACK_SIZE 256



/* Exit to L1 from L2 with RDMSR instruction */

static inline void rdmsr_from_l2(uint32_t msr)

{

	/* Currently, L1 doesn't preserve GPRs during vmexits. */

	__asm__ __volatile__ ("rdmsr" : : "c"(msr) :

			      "rax", "rbx", "rdx", "rsi", "rdi", "r8", "r9",

			      "r10", "r11", "r12", "r13", "r14", "r15");

}



void l2_guest_code(void)

{

	GUEST_SYNC(3);
@@ -30,11 +39,11 @@ void l2_guest_code(void) 
	vmmcall();



	/* MSR-Bitmap tests */

	rdmsr(MSR_FS_BASE); /* intercepted */

	rdmsr(MSR_FS_BASE); /* intercepted */

	rdmsr(MSR_GS_BASE); /* not intercepted */

	rdmsr_from_l2(MSR_FS_BASE); /* intercepted */

	rdmsr_from_l2(MSR_FS_BASE); /* intercepted */

	rdmsr_from_l2(MSR_GS_BASE); /* not intercepted */

	vmmcall();

	rdmsr(MSR_GS_BASE); /* intercepted */

	rdmsr_from_l2(MSR_GS_BASE); /* intercepted */



	GUEST_SYNC(5);