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Message-ID: <20210730143530.GD20232@u366d62d47e3651.ant.amazon.com>
Date: Fri, 30 Jul 2021 16:35:31 +0200
From: Siddharth Chandrasekaran <sidcha@...zon.de>
To: Vitaly Kuznetsov <vkuznets@...hat.com>
CC: <kvm@...r.kernel.org>, Paolo Bonzini <pbonzini@...hat.com>,
Sean Christopherson <seanjc@...gle.com>,
Wanpeng Li <wanpengli@...cent.com>,
Jim Mattson <jmattson@...gle.com>,
<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 4/4] KVM: selftests: Test access to XMM fast hypercalls
On Fri, Jul 30, 2021 at 02:26:25PM +0200, Vitaly Kuznetsov wrote:
> HYPERV_CPUID_FEATURES.EDX and an 'XMM fast' hypercall is issued.
>
> Signed-off-by: Vitaly Kuznetsov <vkuznets@...hat.com>
> ---
> .../selftests/kvm/include/x86_64/hyperv.h | 5 ++-
> .../selftests/kvm/x86_64/hyperv_features.c | 41 +++++++++++++++++--
> 2 files changed, 42 insertions(+), 4 deletions(-)
>
> diff --git a/tools/testing/selftests/kvm/include/x86_64/hyperv.h b/tools/testing/selftests/kvm/include/x86_64/hyperv.h
> index 412eaee7884a..b66910702c0a 100644
> --- a/tools/testing/selftests/kvm/include/x86_64/hyperv.h
> +++ b/tools/testing/selftests/kvm/include/x86_64/hyperv.h
> @@ -117,7 +117,7 @@
> #define HV_X64_GUEST_DEBUGGING_AVAILABLE BIT(1)
> #define HV_X64_PERF_MONITOR_AVAILABLE BIT(2)
> #define HV_X64_CPU_DYNAMIC_PARTITIONING_AVAILABLE BIT(3)
> -#define HV_X64_HYPERCALL_PARAMS_XMM_AVAILABLE BIT(4)
> +#define HV_X64_HYPERCALL_XMM_INPUT_AVAILABLE BIT(4)
> #define HV_X64_GUEST_IDLE_STATE_AVAILABLE BIT(5)
> #define HV_FEATURE_FREQUENCY_MSRS_AVAILABLE BIT(8)
> #define HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE BIT(10)
> @@ -182,4 +182,7 @@
> #define HV_STATUS_INVALID_CONNECTION_ID 18
> #define HV_STATUS_INSUFFICIENT_BUFFERS 19
>
> +/* hypercall options */
> +#define HV_HYPERCALL_FAST_BIT BIT(16)
> +
> #endif /* !SELFTEST_KVM_HYPERV_H */
> diff --git a/tools/testing/selftests/kvm/x86_64/hyperv_features.c b/tools/testing/selftests/kvm/x86_64/hyperv_features.c
> index af27c7e829c1..91d88aaa9899 100644
> --- a/tools/testing/selftests/kvm/x86_64/hyperv_features.c
> +++ b/tools/testing/selftests/kvm/x86_64/hyperv_features.c
> @@ -47,6 +47,7 @@ static void do_wrmsr(u32 idx, u64 val)
> }
>
> static int nr_gp;
> +static int nr_ud;
>
> static inline u64 hypercall(u64 control, vm_vaddr_t input_address,
> vm_vaddr_t output_address)
> @@ -80,6 +81,12 @@ static void guest_gp_handler(struct ex_regs *regs)
> regs->rip = (uint64_t)&wrmsr_end;
> }
>
> +static void guest_ud_handler(struct ex_regs *regs)
> +{
> + nr_ud++;
> + regs->rip += 3;
> +}
> +
> struct msr_data {
> uint32_t idx;
> bool available;
> @@ -90,6 +97,7 @@ struct msr_data {
> struct hcall_data {
> uint64_t control;
> uint64_t expect;
> + bool ud_expected;
> };
>
> static void guest_msr(struct msr_data *msr)
> @@ -117,13 +125,26 @@ static void guest_msr(struct msr_data *msr)
> static void guest_hcall(vm_vaddr_t pgs_gpa, struct hcall_data *hcall)
> {
> int i = 0;
> + u64 res, input, output;
>
> wrmsr(HV_X64_MSR_GUEST_OS_ID, LINUX_OS_ID);
> wrmsr(HV_X64_MSR_HYPERCALL, pgs_gpa);
>
> while (hcall->control) {
> - GUEST_ASSERT(hypercall(hcall->control, pgs_gpa,
> - pgs_gpa + 4096) == hcall->expect);
> + nr_ud = 0;
> + if (!(hcall->control & HV_HYPERCALL_FAST_BIT)) {
> + input = pgs_gpa;
> + output = pgs_gpa + 4096;
> + } else {
> + input = output = 0;
> + }
> +
> + res = hypercall(hcall->control, input, output);
> + if (hcall->ud_expected)
> + GUEST_ASSERT(nr_ud == 1);
Should we also do WRITE_ONCE(nr_ur, 0) here? or perhaps pass the the
expected value of nr_ud + 1 in hcall->ud_expected from caller and do,
if (hcall->ud_expected)
GUEST_ASSERT(nr_ud == hcall->ud_expected);
This way there can be other test that can also expect a UD.
> + else
> + GUEST_ASSERT(res == hcall->expect);
> +
> GUEST_SYNC(i++);
> }
>
> @@ -552,8 +573,18 @@ static void guest_test_hcalls_access(struct kvm_vm *vm, struct hcall_data *hcall
> recomm.ebx = 0xfff;
> hcall->expect = HV_STATUS_SUCCESS;
> break;
> -
> case 17:
> + /* XMM fast hypercall */
> + hcall->control = HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE | HV_HYPERCALL_FAST_BIT;
> + hcall->ud_expected = true;
> + break;
> + case 18:
> + feat.edx |= HV_X64_HYPERCALL_XMM_INPUT_AVAILABLE;
> + hcall->ud_expected = false;
> + hcall->expect = HV_STATUS_SUCCESS;
> + break;
> +
> + case 19:
> /* END */
> hcall->control = 0;
> break;
> @@ -625,6 +656,10 @@ int main(void)
> /* Test hypercalls */
> vm = vm_create_default(VCPU_ID, 0, guest_hcall);
>
> + vm_init_descriptor_tables(vm);
> + vcpu_init_descriptor_tables(vm, VCPU_ID);
> + vm_install_exception_handler(vm, UD_VECTOR, guest_ud_handler);
> +
> /* Hypercall input/output */
> hcall_page = vm_vaddr_alloc_pages(vm, 2);
> memset(addr_gva2hva(vm, hcall_page), 0x0, 2 * getpagesize());
> --
> 2.31.1
>
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