[PATCH 09/25] KVM: TDX: Get system-wide info about TDX module on initialization

Rick Edgecombe
2024-08-12T22:48:36Z

From: Isaku Yamahata <isaku.yamahata@intel.com>

TDX KVM needs system-wide information about the TDX module, store it in
struct tdx_info. Release the allocated memory on module unloading by
hardware_unsetup() callback.

Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Reviewed-by: Binbin Wu <binbin.wu@linux.intel.com>
---
uAPI breakout v1:
- Mention about hardware_unsetup(). (Binbin)
- Added Reviewed-by. (Binbin)
- Eliminated tdx_md_read(). (Kai)
- Include "x86_ops.h" to tdx.c as the patch to initialize TDX module
doesn't include it anymore.
- Introduce tdx_vm_ioctl() as the first tdx func in x86_ops.h

v19:
- Added features0
- Use tdx_sys_metadata_read()
- Fix error recovery path by Yuan

Change v18:
- Newly Added
---
arch/x86/include/uapi/asm/kvm.h | 28 +++++++++++++
arch/x86/kvm/vmx/tdx.c | 70 +++++++++++++++++++++++++++++++++
2 files changed, 98 insertions(+)

diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h
index d91f1bad800e..47caf508cca7 100644
--- a/arch/x86/include/uapi/asm/kvm.h
+++ b/arch/x86/include/uapi/asm/kvm.h
@@ -952,4 +952,32 @@ struct kvm_tdx_cmd {
__u64 hw_error;
};

+#define KVM_TDX_CPUID_NO_SUBLEAF ((__u32)-1)
+
+struct kvm_tdx_cpuid_config {
+ __u32 leaf;
+ __u32 sub_leaf;
+ __u32 eax;
+ __u32 ebx;
+ __u32 ecx;
+ __u32 edx;
+};
+
+/* supported_gpaw */
+#define TDX_CAP_GPAW_48 (1 << 0)
+#define TDX_CAP_GPAW_52 (1 << 1)
+
+struct kvm_tdx_capabilities {
+ __u64 attrs_fixed0;
+ __u64 attrs_fixed1;
+ __u64 xfam_fixed0;
+ __u64 xfam_fixed1;
+ __u32 supported_gpaw;
+ __u32 padding;
+ __u64 reserved[251];
+
+ __u32 nr_cpuid_configs;
+ struct kvm_tdx_cpuid_config cpuid_configs[];
+};
+
#endif /* _ASM_X86_KVM_H */
diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index de14e80d8f3a..90b44ebaf864 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -3,6 +3,7 @@
#include <asm/tdx.h>
#include "capabilities.h"
#include "x86_ops.h"
+#include "mmu.h"
#include "tdx.h"

#undef pr_fmt
@@ -30,6 +31,72 @@ static void __used tdx_guest_keyid_free(int keyid)
ida_free(&tdx_guest_keyid_pool, keyid);
}

+static int tdx_get_capabilities(struct kvm_tdx_cmd *cmd)
+{
+ const struct tdx_sysinfo_td_conf *td_conf = &tdx_sysinfo->td_conf;
+ struct kvm_tdx_capabilities __user *user_caps;
+ struct kvm_tdx_capabilities *caps = NULL;
+ int i, ret = 0;
+
+ /* flags is reserved for future use */
+ if (cmd->flags)
+ return -EINVAL;
+
+ caps = kmalloc(sizeof(*caps), GFP_KERNEL);
+ if (!caps)
+ return -ENOMEM;
+
+ user_caps = u64_to_user_ptr(cmd->data);
+ if (copy_from_user(caps, user_caps, sizeof(*caps))) {
+ ret = -EFAULT;
+ goto out;
+ }
+
+ if (caps->nr_cpuid_configs < td_conf->num_cpuid_config) {
+ ret = -E2BIG;
+ goto out;
+ }
+
+ *caps = (struct kvm_tdx_capabilities) {
+ .attrs_fixed0 = td_conf->attributes_fixed0,
+ .attrs_fixed1 = td_conf->attributes_fixed1,
+ .xfam_fixed0 = td_conf->xfam_fixed0,
+ .xfam_fixed1 = td_conf->xfam_fixed1,
+ .supported_gpaw = TDX_CAP_GPAW_48 |
+ ((kvm_host.maxphyaddr >= 52 &&
+ cpu_has_vmx_ept_5levels()) ? TDX_CAP_GPAW_52 : 0),
+ .nr_cpuid_configs = td_conf->num_cpuid_config,
+ .padding = 0,
+ };
+
+ if (copy_to_user(user_caps, caps, sizeof(*caps))) {
+ ret = -EFAULT;
+ goto out;
+ }
+
+ for (i = 0; i < td_conf->num_cpuid_config; i++) {
+ struct kvm_tdx_cpuid_config cpuid_config = {
+ .leaf = (u32)td_conf->cpuid_config_leaves[i],
+ .sub_leaf = td_conf->cpuid_config_leaves[i] >> 32,
+ .eax = (u32)td_conf->cpuid_config_values[i].eax_ebx,
+ .ebx = td_conf->cpuid_config_values[i].eax_ebx >> 32,
+ .ecx = (u32)td_conf->cpuid_config_values[i].ecx_edx,
+ .edx = td_conf->cpuid_config_values[i].ecx_edx >> 32,
+ };
+
+ if (copy_to_user(&(user_caps->cpuid_configs[i]), &cpuid_config,
+ sizeof(struct kvm_tdx_cpuid_config))) {
+ ret = -EFAULT;
+ break;
+ }
+ }
+
+out:
+ /* kfree() accepts NULL. */
+ kfree(caps);
+ return ret;
+}
+
int tdx_vm_ioctl(struct kvm *kvm, void __user *argp)
{
struct kvm_tdx_cmd tdx_cmd;
@@ -48,6 +115,9 @@ int tdx_vm_ioctl(struct kvm *kvm, void __user *argp)
mutex_lock(&kvm->lock);

switch (tdx_cmd.id) {
+ case KVM_TDX_CAPABILITIES:
+ r = tdx_get_capabilities(&tdx_cmd);
+ break;
default:
r = -EINVAL;
goto out;
--
2.34.1