[RFC PATCH v3 07/31] KVM: selftests: TDX: Use KVM_TDX_CAPABILITIES to validate TDs' attribute configuration

Ackerley Tng
2023-01-21T00:17:20Z

This also exercises the KVM_TDX_CAPABILITIES ioctl.

Suggested-by: Isaku Yamahata <isaku.yamahata@intel.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
.../selftests/kvm/lib/x86_64/tdx/tdx_util.c | 75 ++++++++++++++++++-
1 file changed, 72 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx_util.c b/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx_util.c
index 3564059c0b89b..2e9679d24a843 100644
--- a/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx_util.c
+++ b/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx_util.c
@@ -27,10 +27,9 @@ static char *tdx_cmd_str[] = {
};
#define TDX_MAX_CMD_STR (ARRAY_SIZE(tdx_cmd_str))

-static void tdx_ioctl(int fd, int ioctl_no, uint32_t flags, void *data)
+static int _tdx_ioctl(int fd, int ioctl_no, uint32_t flags, void *data)
{
struct kvm_tdx_cmd tdx_cmd;
- int r;

TEST_ASSERT(ioctl_no < TDX_MAX_CMD_STR, "Unknown TDX CMD : %d\n",
ioctl_no);
@@ -40,11 +39,63 @@ static void tdx_ioctl(int fd, int ioctl_no, uint32_t flags, void *data)
tdx_cmd.flags = flags;
tdx_cmd.data = (uint64_t)data;

- r = ioctl(fd, KVM_MEMORY_ENCRYPT_OP, &tdx_cmd);
+ return ioctl(fd, KVM_MEMORY_ENCRYPT_OP, &tdx_cmd);
+}
+
+static void tdx_ioctl(int fd, int ioctl_no, uint32_t flags, void *data)
+{
+ int r;
+
+ r = _tdx_ioctl(fd, ioctl_no, flags, data);
TEST_ASSERT(r == 0, "%s failed: %d %d", tdx_cmd_str[ioctl_no], r,
errno);
}

+static struct kvm_tdx_capabilities *tdx_read_capabilities(void)
+{
+ int i;
+ int rc = -1;
+ int nr_cpuid_configs = 4;
+ struct kvm_tdx_capabilities *tdx_cap = NULL;
+ int kvm_fd;
+
+ kvm_fd = open_kvm_dev_path_or_exit();
+
+ do {
+ nr_cpuid_configs *= 2;
+
+ tdx_cap = realloc(
+ tdx_cap, sizeof(*tdx_cap) +
+ nr_cpuid_configs * sizeof(*tdx_cap->cpuid_configs));
+ TEST_ASSERT(tdx_cap != NULL,
+ "Could not allocate memory for tdx capability nr_cpuid_configs %d\n",
+ nr_cpuid_configs);
+
+ tdx_cap->nr_cpuid_configs = nr_cpuid_configs;
+ rc = _tdx_ioctl(kvm_fd, KVM_TDX_CAPABILITIES, 0, tdx_cap);
+ } while (rc < 0 && errno == E2BIG);
+
+ TEST_ASSERT(rc == 0, "KVM_TDX_CAPABILITIES failed: %d %d",
+ rc, errno);
+
+ pr_debug("tdx_cap: attrs: fixed0 0x%016llx fixed1 0x%016llx\n"
+ "tdx_cap: xfam fixed0 0x%016llx fixed1 0x%016llx\n",
+ tdx_cap->attrs_fixed0, tdx_cap->attrs_fixed1,
+ tdx_cap->xfam_fixed0, tdx_cap->xfam_fixed1);
+
+ for (i = 0; i < tdx_cap->nr_cpuid_configs; i++) {
+ const struct kvm_tdx_cpuid_config *config =
+ &tdx_cap->cpuid_configs[i];
+ pr_debug("cpuid config[%d]: leaf 0x%x sub_leaf 0x%x eax 0x%08x ebx 0x%08x ecx 0x%08x edx 0x%08x\n",
+ i, config->leaf, config->sub_leaf,
+ config->eax, config->ebx, config->ecx, config->edx);
+ }
+
+ close(kvm_fd);
+
+ return tdx_cap;
+}
+
#define XFEATURE_LBR 15
#define XFEATURE_XTILECFG 17
#define XFEATURE_XTILEDATA 18
@@ -90,6 +141,21 @@ static void tdx_apply_cpuid_restrictions(struct kvm_cpuid2 *cpuid_data)
}
}

+static void tdx_check_attributes(uint64_t attributes)
+{
+ struct kvm_tdx_capabilities *tdx_cap;
+
+ tdx_cap = tdx_read_capabilities();
+
+ /* TDX spec: any bits 0 in attrs_fixed0 must be 0 in attributes */
+ ASSERT_EQ(attributes & ~tdx_cap->attrs_fixed0, 0);
+
+ /* TDX spec: any bits 1 in attrs_fixed1 must be 1 in attributes */
+ ASSERT_EQ(attributes & tdx_cap->attrs_fixed1, tdx_cap->attrs_fixed1);
+
+ free(tdx_cap);
+}
+
static void tdx_td_init(struct kvm_vm *vm, uint64_t attributes)
{
const struct kvm_cpuid2 *cpuid;
@@ -100,6 +166,9 @@ static void tdx_td_init(struct kvm_vm *vm, uint64_t attributes)
cpuid = kvm_get_supported_cpuid();

memcpy(&init_vm.cpuid, cpuid, kvm_cpuid2_size(cpuid->nent));
+
+ tdx_check_attributes(attributes);
+
init_vm.attributes = attributes;

tdx_apply_cpuid_restrictions(&init_vm.cpuid);
--
2.39.0.246.g2a6d74b583-goog