On 26/02/2024 9:25 pm, Yamahata, Isaku wrote:
From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
KVM_MEMORY_ENCRYPT_OP was introduced for VM-scoped operations specific for
guest state-protected VM. It defined subcommands for technology-specific
operations under KVM_MEMORY_ENCRYPT_OP. Despite its name, the subcommands
are not limited to memory encryption, but various technology-specific
operations are defined. It's natural to repurpose KVM_MEMORY_ENCRYPT_OP
for TDX specific operations and define subcommands.
TDX requires VM-scoped TDX-specific operations for device model, for
example, qemu. Getting system-wide parameters, TDX-specific VM
initialization.
-EPARSE for the second sentence (or it is not a valid sentence at all).
Add a place holder function for TDX specific VM-scoped ioctl as mem_enc_op.
TDX specific sub-commands will be added to retrieve/pass TDX specific
parameters. Make mem_enc_ioctl non-optional as it's always filled.
Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
---
v15:
- change struct kvm_tdx_cmd to drop unused member.
---
arch/x86/include/asm/kvm-x86-ops.h | 2 +-
arch/x86/include/uapi/asm/kvm.h | 26 ++++++++++++++++++++++++++
arch/x86/kvm/vmx/main.c | 10 ++++++++++
arch/x86/kvm/vmx/tdx.c | 26 ++++++++++++++++++++++++++
arch/x86/kvm/vmx/x86_ops.h | 4 ++++
arch/x86/kvm/x86.c | 4 ----
6 files changed, 67 insertions(+), 5 deletions(-)
diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h
index 8be71a5c5c87..00b371d9a1ca 100644
--- a/arch/x86/include/asm/kvm-x86-ops.h
+++ b/arch/x86/include/asm/kvm-x86-ops.h
@@ -123,7 +123,7 @@ KVM_X86_OP(enter_smm)
KVM_X86_OP(leave_smm)
KVM_X86_OP(enable_smi_window)
#endif
-KVM_X86_OP_OPTIONAL(mem_enc_ioctl)
+KVM_X86_OP(mem_enc_ioctl)
KVM_X86_OP_OPTIONAL(mem_enc_register_region)
KVM_X86_OP_OPTIONAL(mem_enc_unregister_region)
KVM_X86_OP_OPTIONAL(vm_copy_enc_context_from)
diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h
index 45b2c2304491..9ea46d143bef 100644
--- a/arch/x86/include/uapi/asm/kvm.h
+++ b/arch/x86/include/uapi/asm/kvm.h
@@ -567,6 +567,32 @@ struct kvm_pmu_event_filter {
#define KVM_X86_TDX_VM 2
#define KVM_X86_SNP_VM 3
+/* Trust Domain eXtension sub-ioctl() commands. */
+enum kvm_tdx_cmd_id {
+ KVM_TDX_CAPABILITIES = 0,
+
+ KVM_TDX_CMD_NR_MAX,
+};
+
+struct kvm_tdx_cmd {
+ /* enum kvm_tdx_cmd_id */
+ __u32 id;
+ /* flags for sub-commend. If sub-command doesn't use this, set zero. */
+ __u32 flags;
+ /*
+ * data for each sub-command. An immediate or a pointer to the actual
+ * data in process virtual address. If sub-command doesn't use it,
+ * set zero.
+ */
+ __u64 data;
+ /*
+ * Auxiliary error code. The sub-command may return TDX SEAMCALL
+ * status code in addition to -Exxx.
+ * Defined for consistency with struct kvm_sev_cmd.
+ */
+ __u64 error;
If the 'error' is for SEAMCALL error, should we rename it to 'hw_error'
or 'fw_error' or something similar? I think 'error' is too generic.
+};
+
#define KVM_TDX_CPUID_NO_SUBLEAF ((__u32)-1)
struct kvm_tdx_cpuid_config {
diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
index a948a6959ac7..082e82ce6580 100644
--- a/arch/x86/kvm/vmx/main.c
+++ b/arch/x86/kvm/vmx/main.c
@@ -47,6 +47,14 @@ static int vt_vm_init(struct kvm *kvm)
return vmx_vm_init(kvm);
}
+static int vt_mem_enc_ioctl(struct kvm *kvm, void __user *argp)
+{
+ if (!is_td(kvm))
+ return -ENOTTY;
+
+ return tdx_vm_ioctl(kvm, argp);
+}
+
#define VMX_REQUIRED_APICV_INHIBITS \
(BIT(APICV_INHIBIT_REASON_DISABLE)| \
BIT(APICV_INHIBIT_REASON_ABSENT) | \
@@ -200,6 +208,8 @@ struct kvm_x86_ops vt_x86_ops __initdata = {
.vcpu_deliver_sipi_vector = kvm_vcpu_deliver_sipi_vector,
.get_untagged_addr = vmx_get_untagged_addr,
+
+ .mem_enc_ioctl = vt_mem_enc_ioctl,
};
struct kvm_x86_init_ops vt_init_ops __initdata = {
diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index 5edfb99abb89..07a3f0f75f87 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -55,6 +55,32 @@ struct tdx_info {
/* Info about the TDX module. */
static struct tdx_info *tdx_info;
+int tdx_vm_ioctl(struct kvm *kvm, void __user *argp)
+{
+ struct kvm_tdx_cmd tdx_cmd;
+ int r;
+
+ if (copy_from_user(&tdx_cmd, argp, sizeof(struct kvm_tdx_cmd)))
+ return -EFAULT;
Add an empty line.
+ if (tdx_cmd.error)
+ return -EINVAL;
Add a comment?
/*
* Userspace should never set @error, which is used to fill
* hardware-defined error by the kernel.
*/
+
+ mutex_lock(&kvm->lock);
+
+ switch (tdx_cmd.id) {
+ default:
+ r = -EINVAL;
I am not sure whether you should return -ENOTTY to be consistent with
the previous vt_mem_enc_ioctl() where a TDX-specific IOCTL is issued for
non-TDX guest.
Here I think the invalid @id means the sub-command isn't valid.
+ goto out;
+ }
+
+ if (copy_to_user(argp, &tdx_cmd, sizeof(struct kvm_tdx_cmd)))
+ r = -EFAULT;
+
+out:
+ mutex_unlock(&kvm->lock);
+ return r;
+}
+
