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    Subject[PATCH v5 35/37] KVM: selftests: evmcs_test: Introduce L2 TLB flush test
    Date
    Enable Hyper-V L2 TLB flush and check that Hyper-V TLB flush hypercalls
    from L2 don't exit to L1 unless 'TlbLockCount' is set in the
    Partition assist page.

    Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
    Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
    ---
    .../selftests/kvm/include/x86_64/evmcs.h | 2 +
    .../testing/selftests/kvm/x86_64/evmcs_test.c | 42 ++++++++++++++++++-
    2 files changed, 42 insertions(+), 2 deletions(-)

    diff --git a/tools/testing/selftests/kvm/include/x86_64/evmcs.h b/tools/testing/selftests/kvm/include/x86_64/evmcs.h
    index 9c965ba73dec..36c0a67d8602 100644
    --- a/tools/testing/selftests/kvm/include/x86_64/evmcs.h
    +++ b/tools/testing/selftests/kvm/include/x86_64/evmcs.h
    @@ -252,6 +252,8 @@ struct hv_enlightened_vmcs {
    #define HV_X64_MSR_VP_ASSIST_PAGE_ADDRESS_MASK \
    (~((1ull << HV_X64_MSR_VP_ASSIST_PAGE_ADDRESS_SHIFT) - 1))

    +#define HV_VMX_SYNTHETIC_EXIT_REASON_TRAP_AFTER_FLUSH 0x10000031
    +
    extern struct hv_enlightened_vmcs *current_evmcs;
    extern struct hv_vp_assist_page *current_vp_assist;

    diff --git a/tools/testing/selftests/kvm/x86_64/evmcs_test.c b/tools/testing/selftests/kvm/x86_64/evmcs_test.c
    index e161c6dd7a02..e644622e4b51 100644
    --- a/tools/testing/selftests/kvm/x86_64/evmcs_test.c
    +++ b/tools/testing/selftests/kvm/x86_64/evmcs_test.c
    @@ -16,6 +16,7 @@

    #include "kvm_util.h"

    +#include "hyperv.h"
    #include "vmx.h"

    #define VCPU_ID 5
    @@ -66,15 +67,27 @@ void l2_guest_code(void)
    vmcall();
    rdmsr_gs_base(); /* intercepted */

    + /* L2 TLB flush tests */
    + hyperv_hypercall(HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE | HV_HYPERCALL_FAST_BIT, 0x0,
    + HV_FLUSH_ALL_VIRTUAL_ADDRESS_SPACES | HV_FLUSH_ALL_PROCESSORS);
    + rdmsr_fs_base();
    + hyperv_hypercall(HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE | HV_HYPERCALL_FAST_BIT, 0x0,
    + HV_FLUSH_ALL_VIRTUAL_ADDRESS_SPACES | HV_FLUSH_ALL_PROCESSORS);
    + /* Make sure we're no issuing Hyper-V TLB flush call again */
    + __asm__ __volatile__ ("mov $0xdeadbeef, %rcx");
    +
    /* Done, exit to L1 and never come back. */
    vmcall();
    }

    -void guest_code(struct vmx_pages *vmx_pages)
    +void guest_code(struct vmx_pages *vmx_pages, vm_vaddr_t pgs_gpa)
    {
    #define L2_GUEST_STACK_SIZE 64
    unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE];

    + wrmsr(HV_X64_MSR_GUEST_OS_ID, HYPERV_LINUX_OS_ID);
    + wrmsr(HV_X64_MSR_HYPERCALL, pgs_gpa);
    +
    x2apic_enable();

    GUEST_SYNC(1);
    @@ -104,6 +117,14 @@ void guest_code(struct vmx_pages *vmx_pages)
    vmwrite(PIN_BASED_VM_EXEC_CONTROL, vmreadz(PIN_BASED_VM_EXEC_CONTROL) |
    PIN_BASED_NMI_EXITING);

    + /* L2 TLB flush setup */
    + current_evmcs->partition_assist_page = vmx_pages->partition_assist_gpa;
    + current_evmcs->hv_enlightenments_control.nested_flush_hypercall = 1;
    + current_evmcs->hv_vm_id = 1;
    + current_evmcs->hv_vp_id = 1;
    + current_vp_assist->nested_control.features.directhypercall = 1;
    + *(u32 *)(vmx_pages->partition_assist) = 0;
    +
    GUEST_ASSERT(!vmlaunch());
    GUEST_ASSERT(vmptrstz() == vmx_pages->enlightened_vmcs_gpa);

    @@ -148,6 +169,18 @@ void guest_code(struct vmx_pages *vmx_pages)
    GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_MSR_READ);
    current_evmcs->guest_rip += 2; /* rdmsr */

    + /*
    + * L2 TLB flush test. First VMCALL should be handled directly by L0,
    + * no VMCALL exit expected.
    + */
    + GUEST_ASSERT(!vmresume());
    + GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_MSR_READ);
    + current_evmcs->guest_rip += 2; /* rdmsr */
    + /* Enable synthetic vmexit */
    + *(u32 *)(vmx_pages->partition_assist) = 1;
    + GUEST_ASSERT(!vmresume());
    + GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == HV_VMX_SYNTHETIC_EXIT_REASON_TRAP_AFTER_FLUSH);
    +
    GUEST_ASSERT(!vmresume());
    GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);
    GUEST_SYNC(11);
    @@ -200,6 +233,7 @@ static void save_restore_vm(struct kvm_vm *vm)
    int main(int argc, char *argv[])
    {
    vm_vaddr_t vmx_pages_gva = 0;
    + vm_vaddr_t hcall_page;

    struct kvm_vm *vm;
    struct kvm_run *run;
    @@ -216,11 +250,15 @@ int main(int argc, char *argv[])
    exit(KSFT_SKIP);
    }

    + hcall_page = vm_vaddr_alloc_pages(vm, 1);
    + memset(addr_gva2hva(vm, hcall_page), 0x0, getpagesize());
    +
    vcpu_set_hv_cpuid(vm, VCPU_ID);
    vcpu_enable_evmcs(vm, VCPU_ID);

    vcpu_alloc_vmx(vm, &vmx_pages_gva);
    - vcpu_args_set(vm, VCPU_ID, 1, vmx_pages_gva);
    + vcpu_args_set(vm, VCPU_ID, 2, vmx_pages_gva, addr_gva2gpa(vm, hcall_page));
    + vcpu_set_msr(vm, VCPU_ID, HV_X64_MSR_VP_INDEX, VCPU_ID);

    vm_init_descriptor_tables(vm);
    vcpu_init_descriptor_tables(vm, VCPU_ID);
    --
    2.35.3
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