[PATCH 4/4] KVM: selftests: Test access to XMM fast hypercalls

From: Vitaly Kuznetsov
Date: Fri Jul 30 2021 - 08:26:53 EST


HYPERV_CPUID_FEATURES.EDX and an 'XMM fast' hypercall is issued.

Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
---
.../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);
+ 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