Re: [PATCH v18 003/121] KVM: x86: Add is_vm_type_supported callback

From: Yuan Yao
Date: Mon Jan 29 2024 - 01:54:45 EST

On Mon, Jan 22, 2024 at 03:52:39PM -0800, isaku.yamahata@xxxxxxxxx wrote:
> From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
>
> For TDX, allow the backend can override the supported vm type. Add
> KVM_X86_TDX_VM to reserve the bit.

Please highlight that KVM_X86_SNP_VM is also defined for AMD SEV-SNP
in this patch.

>
> Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
>
> ---
> v18:
> - include into TDX KVM patch series v18
>
> Changes v3 -> v4:
> - Added KVM_X86_SNP_VM
>
> Changes v2 -> v3:
> - no change
> - didn't bother to rename KVM_X86_PROTECTED_VM to KVM_X86_SW_PROTECTED_VM
>
> Changes v1 -> v2
> - no change
> ---
> arch/x86/include/asm/kvm-x86-ops.h | 1 +
> arch/x86/include/asm/kvm_host.h | 1 +
> arch/x86/include/uapi/asm/kvm.h | 2 ++
> arch/x86/kvm/svm/svm.c | 7 +++++++
> arch/x86/kvm/vmx/vmx.c | 7 +++++++
> arch/x86/kvm/x86.c | 12 +++++++++++-
> arch/x86/kvm/x86.h | 2 ++
> 7 files changed, 31 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h
> index 378ed944b849..e6b1763b041d 100644
> --- a/arch/x86/include/asm/kvm-x86-ops.h
> +++ b/arch/x86/include/asm/kvm-x86-ops.h
> @@ -20,6 +20,7 @@ KVM_X86_OP(hardware_disable)
> KVM_X86_OP(hardware_unsetup)
> KVM_X86_OP(has_emulated_msr)
> KVM_X86_OP(vcpu_after_set_cpuid)
> +KVM_X86_OP(is_vm_type_supported)
> KVM_X86_OP(vm_init)
> KVM_X86_OP_OPTIONAL(vm_destroy)
> KVM_X86_OP_OPTIONAL_RET0(vcpu_precreate)
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index 8011bc668d79..26f4668b0273 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -1601,6 +1601,7 @@ struct kvm_x86_ops {
> bool (*has_emulated_msr)(struct kvm *kvm, u32 index);
> void (*vcpu_after_set_cpuid)(struct kvm_vcpu *vcpu);
>
> + bool (*is_vm_type_supported)(unsigned long vm_type);
> unsigned int vm_size;
> int (*vm_init)(struct kvm *kvm);
> void (*vm_destroy)(struct kvm *kvm);
> diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h
> index a448d0964fc0..aa7a56a47564 100644
> --- a/arch/x86/include/uapi/asm/kvm.h
> +++ b/arch/x86/include/uapi/asm/kvm.h
> @@ -564,5 +564,7 @@ struct kvm_pmu_event_filter {
>
> #define KVM_X86_DEFAULT_VM 0
> #define KVM_X86_SW_PROTECTED_VM 1
> +#define KVM_X86_TDX_VM 2
> +#define KVM_X86_SNP_VM 3
>
> #endif /* _ASM_X86_KVM_H */
> diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
> index e90b429c84f1..f76dd52d29ba 100644
> --- a/arch/x86/kvm/svm/svm.c
> +++ b/arch/x86/kvm/svm/svm.c
> @@ -4886,6 +4886,12 @@ static void svm_vm_destroy(struct kvm *kvm)
> sev_vm_destroy(kvm);
> }
>
> +static bool svm_is_vm_type_supported(unsigned long type)
> +{
> + /* FIXME: Check if CPU is capable of SEV-SNP. */
> + return __kvm_is_vm_type_supported(type);
> +}
> +
> static int svm_vm_init(struct kvm *kvm)
> {
> if (!pause_filter_count || !pause_filter_thresh)
> @@ -4914,6 +4920,7 @@ static struct kvm_x86_ops svm_x86_ops __initdata = {
> .vcpu_free = svm_vcpu_free,
> .vcpu_reset = svm_vcpu_reset,
>
> + .is_vm_type_supported = svm_is_vm_type_supported,
> .vm_size = sizeof(struct kvm_svm),
> .vm_init = svm_vm_init,
> .vm_destroy = svm_vm_destroy,
> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
> index e262bc2ba4e5..8fad7bba6d5f 100644
> --- a/arch/x86/kvm/vmx/vmx.c
> +++ b/arch/x86/kvm/vmx/vmx.c
> @@ -7541,6 +7541,12 @@ static int vmx_vcpu_create(struct kvm_vcpu *vcpu)
> return err;
> }
>
> +static bool vmx_is_vm_type_supported(unsigned long type)
> +{
> + /* TODO: Check if TDX is supported. */
> + return __kvm_is_vm_type_supported(type);
> +}
> +
> #define L1TF_MSG_SMT "L1TF CPU bug present and SMT on, data leak possible. See CVE-2018-3646 and https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/l1tf.html for details.\n"
> #define L1TF_MSG_L1D "L1TF CPU bug present and virtualization mitigation disabled, data leak possible. See CVE-2018-3646 and https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/l1tf.html for details.\n"
>
> @@ -8263,6 +8269,7 @@ static struct kvm_x86_ops vmx_x86_ops __initdata = {
> .hardware_disable = vmx_hardware_disable,
> .has_emulated_msr = vmx_has_emulated_msr,
>
> + .is_vm_type_supported = vmx_is_vm_type_supported,
> .vm_size = sizeof(struct kvm_vmx),
> .vm_init = vmx_vm_init,
> .vm_destroy = vmx_vm_destroy,
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 363b1c080205..1b1045dc8e7a 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -4577,12 +4577,18 @@ static int kvm_ioctl_get_supported_hv_cpuid(struct kvm_vcpu *vcpu,
> }
> #endif
>
> -static bool kvm_is_vm_type_supported(unsigned long type)
> +bool __kvm_is_vm_type_supported(unsigned long type)
> {
> return type == KVM_X86_DEFAULT_VM ||
> (type == KVM_X86_SW_PROTECTED_VM &&
> IS_ENABLED(CONFIG_KVM_SW_PROTECTED_VM) && tdp_enabled);
> }
> +EXPORT_SYMBOL_GPL(__kvm_is_vm_type_supported);
> +
> +static bool kvm_is_vm_type_supported(unsigned long type)
> +{
> + return static_call(kvm_x86_is_vm_type_supported)(type);
> +}
>
> int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
> {
> @@ -4784,6 +4790,10 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
> r = BIT(KVM_X86_DEFAULT_VM);
> if (kvm_is_vm_type_supported(KVM_X86_SW_PROTECTED_VM))
> r |= BIT(KVM_X86_SW_PROTECTED_VM);
> + if (kvm_is_vm_type_supported(KVM_X86_TDX_VM))
> + r |= BIT(KVM_X86_TDX_VM);
> + if (kvm_is_vm_type_supported(KVM_X86_SNP_VM))
> + r |= BIT(KVM_X86_SNP_VM);
> break;
> default:
> break;
> diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
> index 2f7e19166658..4e40c23d66ed 100644
> --- a/arch/x86/kvm/x86.h
> +++ b/arch/x86/kvm/x86.h
> @@ -9,6 +9,8 @@
> #include "kvm_cache_regs.h"
> #include "kvm_emulate.h"
>
> +bool __kvm_is_vm_type_supported(unsigned long type);
> +
> struct kvm_caps {
> /* control of guest tsc rate supported? */
> bool has_tsc_control;
> --
> 2.25.1
>
>