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    SubjectRe: [RFC PATCH v4 7/7] KVM: selftests: Add tests for VM and vCPU cap KVM_CAP_X86_DISABLE_EXITS
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    On 6/22/2022 8:49 AM, Kechen Lu wrote:
    > Add tests for KVM cap KVM_CAP_X86_DISABLE_EXITS overriding flags
    > in VM and vCPU scope both works as expected.
    >
    > Suggested-by: Chao Gao <chao.gao@intel.com>
    > Signed-off-by: Kechen Lu <kechenl@nvidia.com>
    > ---
    > tools/testing/selftests/kvm/.gitignore | 1 +
    > tools/testing/selftests/kvm/Makefile | 1 +
    > .../selftests/kvm/include/x86_64/svm_util.h | 1 +
    > .../selftests/kvm/x86_64/disable_exits_test.c | 145 ++++++++++++++++++
    > 4 files changed, 148 insertions(+)
    > create mode 100644 tools/testing/selftests/kvm/x86_64/disable_exits_test.c
    >
    > diff --git a/tools/testing/selftests/kvm/.gitignore b/tools/testing/selftests/kvm/.gitignore
    > index 4509a3a7eeae..2b50170db9b2 100644
    > --- a/tools/testing/selftests/kvm/.gitignore
    > +++ b/tools/testing/selftests/kvm/.gitignore
    > @@ -15,6 +15,7 @@
    > /x86_64/cpuid_test
    > /x86_64/cr4_cpuid_sync_test
    > /x86_64/debug_regs
    > +/x86_64/disable_exits_test
    > /x86_64/evmcs_test
    > /x86_64/emulator_error_test
    > /x86_64/fix_hypercall_test
    > diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
    > index 22423c871ed6..de11d1f95700 100644
    > --- a/tools/testing/selftests/kvm/Makefile
    > +++ b/tools/testing/selftests/kvm/Makefile
    > @@ -115,6 +115,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/xen_shinfo_test
    > TEST_GEN_PROGS_x86_64 += x86_64/xen_vmcall_test
    > TEST_GEN_PROGS_x86_64 += x86_64/sev_migrate_tests
    > TEST_GEN_PROGS_x86_64 += x86_64/amx_test
    > +TEST_GEN_PROGS_x86_64 += x86_64/disable_exits_test
    > TEST_GEN_PROGS_x86_64 += access_tracking_perf_test
    > TEST_GEN_PROGS_x86_64 += demand_paging_test
    > TEST_GEN_PROGS_x86_64 += dirty_log_test
    > diff --git a/tools/testing/selftests/kvm/include/x86_64/svm_util.h b/tools/testing/selftests/kvm/include/x86_64/svm_util.h
    > index a25aabd8f5e7..d8cad1cff578 100644
    > --- a/tools/testing/selftests/kvm/include/x86_64/svm_util.h
    > +++ b/tools/testing/selftests/kvm/include/x86_64/svm_util.h
    > @@ -17,6 +17,7 @@
    > #define CPUID_SVM BIT_ULL(CPUID_SVM_BIT)
    >
    > #define SVM_EXIT_MSR 0x07c
    > +#define SVM_EXIT_HLT 0x078

    There has other people add the SVM_EXIT_HLT in the kvm/queue, so you may
    not need to add it here.

    > #define SVM_EXIT_VMMCALL 0x081
    >
    > struct svm_test_data {
    > diff --git a/tools/testing/selftests/kvm/x86_64/disable_exits_test.c b/tools/testing/selftests/kvm/x86_64/disable_exits_test.c
    > new file mode 100644
    > index 000000000000..2811b07e8885
    > --- /dev/null
    > +++ b/tools/testing/selftests/kvm/x86_64/disable_exits_test.c
    > @@ -0,0 +1,145 @@
    > +// SPDX-License-Identifier: GPL-2.0-only
    > +/*
    > + * Test per-VM and per-vCPU disable exits cap
    > + *
    > + */
    > +
    > +#define _GNU_SOURCE /* for program_invocation_short_name */
    > +#include <sys/ioctl.h>
    > +
    > +#include "test_util.h"
    > +#include "kvm_util.h"
    > +#include "svm_util.h"
    > +#include "vmx.h"
    > +#include "processor.h"
    > +
    > +#define VCPU_ID_1 0
    > +#define VCPU_ID_2 1
    > +
    > +static void guest_code_exits(void) {
    > + asm volatile("sti; hlt; cli");
    > +}
    > +
    > +/* Set debug control for trapped instruction exiting to userspace */
    > +static void vcpu_set_debug_exit_userspace(struct kvm_vm *vm, int vcpu_id) {

    nit: you should make the code style consistent, please use the format:
    function()
    {

    }

    > + struct kvm_guest_debug debug;
    > + memset(&debug, 0, sizeof(debug));
    > + debug.control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_EXIT_USERSPACE;
    > + vcpu_set_guest_debug(vm, vcpu_id, &debug);
    > +}
    > +
    > +static void test_vm_cap_disable_exits(void) {
    > + struct kvm_enable_cap cap = {
    > + .cap = KVM_CAP_X86_DISABLE_EXITS,
    > + .args[0] = KVM_X86_DISABLE_EXITS_HLT|KVM_X86_DISABLE_EXITS_OVERRIDE,
    ^
    nit: a space is much more clear here

    > + };
    > + struct kvm_vm *vm;
    > + struct kvm_run *run;
    > +
    > + /* Create VM */
    > + vm = vm_create_without_vcpus(VM_MODE_DEFAULT, DEFAULT_GUEST_PHY_PAGES);
    > +
    > + /* Test Case #1
    > + * Default without disabling HLT exits in VM scope
    > + */
    > + vm_vcpu_add_default(vm, VCPU_ID_1, (void *)guest_code_exits);
    > + vcpu_set_debug_exit_userspace(vm, VCPU_ID_1);
    > + run = vcpu_state(vm, VCPU_ID_1);
    > + vcpu_run(vm, VCPU_ID_1);
    > + /* Exit reason should be HLT */
    > + if (is_amd_cpu())
    > + TEST_ASSERT(run->hw.hardware_exit_reason == SVM_EXIT_HLT,
    > + "Got exit_reason other than HLT: 0x%llx\n",
    > + run->hw.hardware_exit_reason);
    > + else
    > + TEST_ASSERT(run->hw.hardware_exit_reason == EXIT_REASON_HLT,
    > + "Got exit_reason other than HLT: 0x%llx\n",
    > + run->hw.hardware_exit_reason);
    > +
    > + /* Test Case #2
    > + * Disabling HLT exits in VM scope
    > + */
    > + vm_vcpu_add_default(vm, VCPU_ID_2, (void *)guest_code_exits);
    > + vcpu_set_debug_exit_userspace(vm, VCPU_ID_2);
    > + run = vcpu_state(vm, VCPU_ID_2);

    I think you can add more vcpu here to make sure after disabling HLT
    exits in VM scope here, every vcpu will not exit due to the HLT.

    > + /* Set VM scoped cap arg
    > + * KVM_X86_DISABLE_EXITS_HLT|KVM_X86_DISABLE_EXITS_OVERRIDE
    > + * after vCPUs creation so requiring override flag
    > + */
    > + TEST_ASSERT(!vm_enable_cap(vm, &cap), "Failed to set KVM_CAP_X86_DISABLE_EXITS");
    > + vcpu_run(vm, VCPU_ID_2);
    > + /* Exit reason should not be HLT, would finish the guest
    > + * running and exit (e.g. SVM_EXIT_SHUTDOWN)
    > + */
    > + if (is_amd_cpu())
    > + TEST_ASSERT(run->hw.hardware_exit_reason != SVM_EXIT_HLT,
    > + "Got exit_reason as HLT: 0x%llx\n",
    > + run->hw.hardware_exit_reason);
    > + else
    > + TEST_ASSERT(run->hw.hardware_exit_reason != EXIT_REASON_HLT,
    > + "Got exit_reason as HLT: 0x%llx\n",
    > + run->hw.hardware_exit_reason);
    > +
    > + kvm_vm_free(vm);
    > +}
    > +
    > +static void test_vcpu_cap_disable_exits(void) {
    > + struct kvm_enable_cap cap = {
    > + .cap = KVM_CAP_X86_DISABLE_EXITS,
    > + .args[0] = KVM_X86_DISABLE_EXITS_HLT|KVM_X86_DISABLE_EXITS_OVERRIDE,
    > + };
    > + struct kvm_vm *vm;
    > + struct kvm_run *run;
    > +
    > + /* Create VM */
    > + vm = vm_create_without_vcpus(VM_MODE_DEFAULT, DEFAULT_GUEST_PHY_PAGES);
    > + vm_vcpu_add_default(vm, VCPU_ID_1, (void *)guest_code_exits);
    > + vcpu_set_debug_exit_userspace(vm, VCPU_ID_1);
    > + vm_vcpu_add_default(vm, VCPU_ID_2, (void *)guest_code_exits);
    > + vcpu_set_debug_exit_userspace(vm, VCPU_ID_2);
    > + /* Set vCPU 2 scoped cap arg
    > + * KVM_X86_DISABLE_EXITS_HLT|KVM_X86_DISABLE_EXITS_OVERRIDE
    > + */
    > + TEST_ASSERT(!vcpu_enable_cap(vm, VCPU_ID_2, &cap), "Failed to set KVM_CAP_X86_DISABLE_EXITS");
    > +
    > + /* Test Case #3
    > + * Default without disabling HLT exits in this vCPU 1
    > + */
    > + run = vcpu_state(vm, VCPU_ID_1);
    > + vcpu_run(vm, VCPU_ID_1);
    > + /* Exit reason should be HLT */
    > + if (is_amd_cpu())
    > + TEST_ASSERT(run->hw.hardware_exit_reason == SVM_EXIT_HLT,
    > + "Got exit_reason other than HLT: 0x%llx\n",
    > + run->hw.hardware_exit_reason);
    > + else
    > + TEST_ASSERT(run->hw.hardware_exit_reason == EXIT_REASON_HLT,
    > + "Got exit_reason other than HLT: 0x%llx\n",
    > + run->hw.hardware_exit_reason);
    > +
    > + /* Test Case #4
    > + * Disabling HLT exits in vCPU 2
    > + */
    > + run = vcpu_state(vm, VCPU_ID_2);
    > + vcpu_run(vm, VCPU_ID_2);
    > + /* Exit reason should not be HLT, would finish the guest
    > + * running and exit (e.g. SVM_EXIT_SHUTDOWN)
    > + */
    > + if (is_amd_cpu())
    > + TEST_ASSERT(run->hw.hardware_exit_reason != SVM_EXIT_HLT,
    > + "Got exit_reason as HLT: 0x%llx\n",
    > + run->hw.hardware_exit_reason);
    > + else
    > + TEST_ASSERT(run->hw.hardware_exit_reason != EXIT_REASON_HLT,
    > + "Got exit_reason as HLT: 0x%llx\n",
    > + run->hw.hardware_exit_reason);
    > +
    > + kvm_vm_free(vm);
    > +}
    > +
    > +int main(int argc, char *argv[])
    > +{
    > + test_vm_cap_disable_exits();
    > + test_vcpu_cap_disable_exits();
    > + return 0;
    > +}

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