[PATCH v6 19/21] kvm: selftests: Add support for KVM_CAP_XSAVE2

Paolo Bonzini
2022-01-07T18:55:47Z

From: Wei Wang <wei.w.wang@intel.com>

When KVM_CAP_XSAVE2 is supported, userspace is expected to allocate
buffer for KVM_GET_XSAVE2 and KVM_SET_XSAVE using the size returned
by KVM_CHECK_EXTENSION(KVM_CAP_XSAVE2).

Signed-off-by: Wei Wang <wei.w.wang@intel.com>
Signed-off-by: Guang Zeng <guang.zeng@intel.com>
Signed-off-by: Jing Liu <jing2.liu@intel.com>
Signed-off-by: Yang Zhong <yang.zhong@intel.com>
Message-Id: <20220105123532.12586-20-yang.zhong@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
tools/arch/x86/include/uapi/asm/kvm.h | 16 ++++-
tools/include/uapi/linux/kvm.h | 3 +
.../selftests/kvm/include/kvm_util_base.h | 2 +
.../selftests/kvm/include/x86_64/processor.h | 10 +++
tools/testing/selftests/kvm/lib/kvm_util.c | 32 +++++++++
.../selftests/kvm/lib/x86_64/processor.c | 67 ++++++++++++++++++-
.../testing/selftests/kvm/x86_64/evmcs_test.c | 2 +-
tools/testing/selftests/kvm/x86_64/smm_test.c | 2 +-
.../testing/selftests/kvm/x86_64/state_test.c | 2 +-
.../kvm/x86_64/vmx_preemption_timer_test.c | 2 +-
10 files changed, 130 insertions(+), 8 deletions(-)

diff --git a/tools/arch/x86/include/uapi/asm/kvm.h b/tools/arch/x86/include/uapi/asm/kvm.h
index 5a776a08f78c..2da3316bb559 100644
--- a/tools/arch/x86/include/uapi/asm/kvm.h
+++ b/tools/arch/x86/include/uapi/asm/kvm.h
@@ -373,9 +373,23 @@ struct kvm_debugregs {
__u64 reserved[9];
};

-/* for KVM_CAP_XSAVE */
+/* for KVM_CAP_XSAVE and KVM_CAP_XSAVE2 */
struct kvm_xsave {
+ /*
+ * KVM_GET_XSAVE2 and KVM_SET_XSAVE write and read as many bytes
+ * as are returned by KVM_CHECK_EXTENSION(KVM_CAP_XSAVE2)
+ * respectively, when invoked on the vm file descriptor.
+ *
+ * The size value returned by KVM_CHECK_EXTENSION(KVM_CAP_XSAVE2)
+ * will always be at least 4096. Currently, it is only greater
+ * than 4096 if a dynamic feature has been enabled with
+ * ``arch_prctl()``, but this may change in the future.
+ *
+ * The offsets of the state save areas in struct kvm_xsave follow
+ * the contents of CPUID leaf 0xD on the host.
+ */
__u32 region[1024];
+ __u32 extra[0];
};

#define KVM_MAX_XCRS 16
diff --git a/tools/include/uapi/linux/kvm.h b/tools/include/uapi/linux/kvm.h
index 1daa45268de2..f066637ee206 100644
--- a/tools/include/uapi/linux/kvm.h
+++ b/tools/include/uapi/linux/kvm.h
@@ -1131,6 +1131,7 @@ struct kvm_ppc_resize_hpt {
#define KVM_CAP_EXIT_ON_EMULATION_FAILURE 204
#define KVM_CAP_ARM_MTE 205
#define KVM_CAP_VM_MOVE_ENC_CONTEXT_FROM 206
+#define KVM_CAP_XSAVE2 207

#ifdef KVM_CAP_IRQ_ROUTING

@@ -1551,6 +1552,8 @@ struct kvm_s390_ucas_mapping {
/* Available with KVM_CAP_XSAVE */
#define KVM_GET_XSAVE _IOR(KVMIO, 0xa4, struct kvm_xsave)
#define KVM_SET_XSAVE _IOW(KVMIO, 0xa5, struct kvm_xsave)
+/* Available with KVM_CAP_XSAVE2 */
+#define KVM_GET_XSAVE2 _IOR(KVMIO, 0xcf, struct kvm_xsave)
/* Available with KVM_CAP_XCRS */
#define KVM_GET_XCRS _IOR(KVMIO, 0xa6, struct kvm_xcrs)
#define KVM_SET_XCRS _IOW(KVMIO, 0xa7, struct kvm_xcrs)
diff --git a/tools/testing/selftests/kvm/include/kvm_util_base.h b/tools/testing/selftests/kvm/include/kvm_util_base.h
index 1e5ab6a92848..66775de26952 100644
--- a/tools/testing/selftests/kvm/include/kvm_util_base.h
+++ b/tools/testing/selftests/kvm/include/kvm_util_base.h
@@ -103,6 +103,7 @@ extern const struct vm_guest_mode_params vm_guest_mode_params[];
int open_path_or_exit(const char *path, int flags);
int open_kvm_dev_path_or_exit(void);
int kvm_check_cap(long cap);
+int vm_check_cap(struct kvm_vm *vm, long cap);
int vm_enable_cap(struct kvm_vm *vm, struct kvm_enable_cap *cap);
int vcpu_enable_cap(struct kvm_vm *vm, uint32_t vcpu_id,
struct kvm_enable_cap *cap);
@@ -344,6 +345,7 @@ struct kvm_vm *vm_create_with_vcpus(enum vm_guest_mode mode, uint32_t nr_vcpus,
* guest_code - The vCPU's entry point
*/
void vm_vcpu_add_default(struct kvm_vm *vm, uint32_t vcpuid, void *guest_code);
+void vm_xsave_req_perm(void);

bool vm_is_unrestricted_guest(struct kvm_vm *vm);

diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h
index 05e65ca1c30c..58633e51960f 100644
--- a/tools/testing/selftests/kvm/include/x86_64/processor.h
+++ b/tools/testing/selftests/kvm/include/x86_64/processor.h
@@ -10,8 +10,10 @@

#include <assert.h>
#include <stdint.h>
+#include <syscall.h>

#include <asm/msr-index.h>
+#include <asm/prctl.h>

#include "../kvm_util.h"

@@ -352,6 +354,7 @@ struct kvm_x86_state;
struct kvm_x86_state *vcpu_save_state(struct kvm_vm *vm, uint32_t vcpuid);
void vcpu_load_state(struct kvm_vm *vm, uint32_t vcpuid,
struct kvm_x86_state *state);
+void kvm_x86_state_cleanup(struct kvm_x86_state *state);

struct kvm_msr_list *kvm_get_msr_index_list(void);
uint64_t kvm_get_feature_msr(uint64_t msr_index);
@@ -443,4 +446,11 @@ void __virt_pg_map(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr,
/* VMX_EPT_VPID_CAP bits */
#define VMX_EPT_VPID_CAP_AD_BITS (1ULL << 21)

+#define XSTATE_XTILE_CFG_BIT 17
+#define XSTATE_XTILE_DATA_BIT 18
+
+#define XSTATE_XTILE_CFG_MASK (1ULL << XSTATE_XTILE_CFG_BIT)
+#define XSTATE_XTILE_DATA_MASK (1ULL << XSTATE_XTILE_DATA_BIT)
+#define XFEATURE_XTILE_MASK (XSTATE_XTILE_CFG_MASK | \
+ XSTATE_XTILE_DATA_MASK)
#endif /* SELFTEST_KVM_PROCESSOR_H */
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index ecc53d108ad8..4a645dc77f34 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -85,6 +85,33 @@ int kvm_check_cap(long cap)
return ret;
}

+/* VM Check Capability
+ *
+ * Input Args:
+ * vm - Virtual Machine
+ * cap - Capability
+ *
+ * Output Args: None
+ *
+ * Return:
+ * On success, the Value corresponding to the capability (KVM_CAP_*)
+ * specified by the value of cap. On failure a TEST_ASSERT failure
+ * is produced.
+ *
+ * Looks up and returns the value corresponding to the capability
+ * (KVM_CAP_*) given by cap.
+ */
+int vm_check_cap(struct kvm_vm *vm, long cap)
+{
+ int ret;
+
+ ret = ioctl(vm->fd, KVM_CHECK_EXTENSION, cap);
+ TEST_ASSERT(ret >= 0, "KVM_CHECK_EXTENSION VM IOCTL failed,\n"
+ " rc: %i errno: %i", ret, errno);
+
+ return ret;
+}
+
/* VM Enable Capability
*
* Input Args:
@@ -366,6 +393,11 @@ struct kvm_vm *vm_create_with_vcpus(enum vm_guest_mode mode, uint32_t nr_vcpus,
struct kvm_vm *vm;
int i;

+ /*
+ * Permission needs to be requested before KVM_SET_CPUID2.
+ */
+ vm_xsave_req_perm();
+
/* Force slot0 memory size not small than DEFAULT_GUEST_PHY_PAGES */
if (slot0_mem_pages < DEFAULT_GUEST_PHY_PAGES)
slot0_mem_pages = DEFAULT_GUEST_PHY_PAGES;
diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c
index eef7b34756d5..f19d6d201977 100644
--- a/tools/testing/selftests/kvm/lib/x86_64/processor.c
+++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c
@@ -650,6 +650,45 @@ static void vcpu_setup(struct kvm_vm *vm, int vcpuid)
vcpu_sregs_set(vm, vcpuid, &sregs);
}

+#define CPUID_XFD_BIT (1 << 4)
+static bool is_xfd_supported(void)
+{
+ int eax, ebx, ecx, edx;
+ const int leaf = 0xd, subleaf = 0x1;
+
+ __asm__ __volatile__(
+ "cpuid"
+ : /* output */ "=a"(eax), "=b"(ebx),
+ "=c"(ecx), "=d"(edx)
+ : /* input */ "0"(leaf), "2"(subleaf));
+
+ return !!(eax & CPUID_XFD_BIT);
+}
+
+void vm_xsave_req_perm(void)
+{
+ unsigned long bitmask;
+ long rc;
+
+ if (!is_xfd_supported())
+ return;
+
+ rc = syscall(SYS_arch_prctl, ARCH_REQ_XCOMP_GUEST_PERM,
+ XSTATE_XTILE_DATA_BIT);
+ /*
+ * The older kernel version(<5.15) can't support
+ * ARCH_REQ_XCOMP_GUEST_PERM and directly return.
+ */
+ if (rc)
+ return;
+
+ rc = syscall(SYS_arch_prctl, ARCH_GET_XCOMP_GUEST_PERM, &bitmask);
+ TEST_ASSERT(rc == 0, "prctl(ARCH_GET_XCOMP_GUEST_PERM) error: %ld", rc);
+ TEST_ASSERT(bitmask & XFEATURE_XTILE_MASK,
+ "prctl(ARCH_REQ_XCOMP_GUEST_PERM) failure bitmask=0x%lx",
+ bitmask);
+}
+
void vm_vcpu_add_default(struct kvm_vm *vm, uint32_t vcpuid, void *guest_code)
{
struct kvm_mp_state mp_state;
@@ -1018,10 +1057,10 @@ void vcpu_dump(FILE *stream, struct kvm_vm *vm, uint32_t vcpuid, uint8_t indent)
}

struct kvm_x86_state {
+ struct kvm_xsave *xsave;
struct kvm_vcpu_events events;
struct kvm_mp_state mp_state;
struct kvm_regs regs;
- struct kvm_xsave xsave;
struct kvm_xcrs xcrs;
struct kvm_sregs sregs;
struct kvm_debugregs debugregs;
@@ -1069,6 +1108,22 @@ struct kvm_msr_list *kvm_get_msr_index_list(void)
return list;
}

+static int vcpu_save_xsave_state(struct kvm_vm *vm, struct vcpu *vcpu,
+ struct kvm_x86_state *state)
+{
+ int size;
+
+ size = vm_check_cap(vm, KVM_CAP_XSAVE2);
+ if (!size)
+ size = sizeof(struct kvm_xsave);
+
+ state->xsave = malloc(size);
+ if (size == sizeof(struct kvm_xsave))
+ return ioctl(vcpu->fd, KVM_GET_XSAVE, state->xsave);
+ else
+ return ioctl(vcpu->fd, KVM_GET_XSAVE2, state->xsave);
+}
+
struct kvm_x86_state *vcpu_save_state(struct kvm_vm *vm, uint32_t vcpuid)
{
struct vcpu *vcpu = vcpu_find(vm, vcpuid);
@@ -1112,7 +1167,7 @@ struct kvm_x86_state *vcpu_save_state(struct kvm_vm *vm, uint32_t vcpuid)
TEST_ASSERT(r == 0, "Unexpected result from KVM_GET_REGS, r: %i",
r);

- r = ioctl(vcpu->fd, KVM_GET_XSAVE, &state->xsave);
+ r = vcpu_save_xsave_state(vm, vcpu, state);
TEST_ASSERT(r == 0, "Unexpected result from KVM_GET_XSAVE, r: %i",
r);

@@ -1157,7 +1212,7 @@ void vcpu_load_state(struct kvm_vm *vm, uint32_t vcpuid, struct kvm_x86_state *s
struct vcpu *vcpu = vcpu_find(vm, vcpuid);
int r;

- r = ioctl(vcpu->fd, KVM_SET_XSAVE, &state->xsave);
+ r = ioctl(vcpu->fd, KVM_SET_XSAVE, state->xsave);
TEST_ASSERT(r == 0, "Unexpected result from KVM_SET_XSAVE, r: %i",
r);

@@ -1198,6 +1253,12 @@ void vcpu_load_state(struct kvm_vm *vm, uint32_t vcpuid, struct kvm_x86_state *s
}
}

+void kvm_x86_state_cleanup(struct kvm_x86_state *state)
+{
+ free(state->xsave);
+ free(state);
+}
+
bool is_intel_cpu(void)
{
int eax, ebx, ecx, edx;
diff --git a/tools/testing/selftests/kvm/x86_64/evmcs_test.c b/tools/testing/selftests/kvm/x86_64/evmcs_test.c
index 2b46dcca86a8..4c7841dfd481 100644
--- a/tools/testing/selftests/kvm/x86_64/evmcs_test.c
+++ b/tools/testing/selftests/kvm/x86_64/evmcs_test.c
@@ -129,7 +129,7 @@ static void save_restore_vm(struct kvm_vm *vm)
vcpu_set_hv_cpuid(vm, VCPU_ID);
vcpu_enable_evmcs(vm, VCPU_ID);
vcpu_load_state(vm, VCPU_ID, state);
- free(state);
+ kvm_x86_state_cleanup(state);

memset(&regs2, 0, sizeof(regs2));
vcpu_regs_get(vm, VCPU_ID, &regs2);
diff --git a/tools/testing/selftests/kvm/x86_64/smm_test.c b/tools/testing/selftests/kvm/x86_64/smm_test.c
index d0fe2fdce58c..2da8eb8e2d96 100644
--- a/tools/testing/selftests/kvm/x86_64/smm_test.c
+++ b/tools/testing/selftests/kvm/x86_64/smm_test.c
@@ -212,7 +212,7 @@ int main(int argc, char *argv[])
vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid());
vcpu_load_state(vm, VCPU_ID, state);
run = vcpu_state(vm, VCPU_ID);
- free(state);
+ kvm_x86_state_cleanup(state);
}

done:
diff --git a/tools/testing/selftests/kvm/x86_64/state_test.c b/tools/testing/selftests/kvm/x86_64/state_test.c
index 32854c1462ad..2e0a92da8ff5 100644
--- a/tools/testing/selftests/kvm/x86_64/state_test.c
+++ b/tools/testing/selftests/kvm/x86_64/state_test.c
@@ -218,7 +218,7 @@ int main(int argc, char *argv[])
vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid());
vcpu_load_state(vm, VCPU_ID, state);
run = vcpu_state(vm, VCPU_ID);
- free(state);
+ kvm_x86_state_cleanup(state);

memset(&regs2, 0, sizeof(regs2));
vcpu_regs_get(vm, VCPU_ID, &regs2);
diff --git a/tools/testing/selftests/kvm/x86_64/vmx_preemption_timer_test.c b/tools/testing/selftests/kvm/x86_64/vmx_preemption_timer_test.c
index a07480aed397..ff92e25b6f1e 100644
--- a/tools/testing/selftests/kvm/x86_64/vmx_preemption_timer_test.c
+++ b/tools/testing/selftests/kvm/x86_64/vmx_preemption_timer_test.c
@@ -244,7 +244,7 @@ int main(int argc, char *argv[])
vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid());
vcpu_load_state(vm, VCPU_ID, state);
run = vcpu_state(vm, VCPU_ID);
- free(state);
+ kvm_x86_state_cleanup(state);

memset(&regs2, 0, sizeof(regs2));
vcpu_regs_get(vm, VCPU_ID, &regs2);
--
2.31.1