From 75ee7505feae16bbfbed62115e04f762047c4765 Mon Sep 17 00:00:00 2001 From: Vitaly Kuznetsov Date: Tue, 1 Nov 2022 15:54:23 +0100 Subject: [PATCH] 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: Vitaly Kuznetsov Signed-off-by: Paolo Bonzini Message-Id: <20221101145426.251680-46-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini --- tools/testing/selftests/kvm/x86_64/evmcs_test.c | 27 ++++++++-------------- .../testing/selftests/kvm/x86_64/hyperv_svm_test.c | 17 ++++++++++---- 2 files changed, 23 insertions(+), 21 deletions(-) diff --git a/tools/testing/selftests/kvm/x86_64/evmcs_test.c b/tools/testing/selftests/kvm/x86_64/evmcs_test.c index 74f076b..58fa985 100644 --- a/tools/testing/selftests/kvm/x86_64/evmcs_test.c +++ b/tools/testing/selftests/kvm/x86_64/evmcs_test.c @@ -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(); diff --git a/tools/testing/selftests/kvm/x86_64/hyperv_svm_test.c b/tools/testing/selftests/kvm/x86_64/hyperv_svm_test.c index 1c3fc38..3c9a2a1 100644 --- a/tools/testing/selftests/kvm/x86_64/hyperv_svm_test.c +++ b/tools/testing/selftests/kvm/x86_64/hyperv_svm_test.c @@ -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); -- 2.7.4