Commit 61bb2827 authored by Isaku Yamahata's avatar Isaku Yamahata Committed by Paolo Bonzini
Browse files

KVM: TDX: Get system-wide info about TDX module on initialization 



TDX KVM needs system-wide information about the TDX module. Generate the
data based on tdx_sysinfo td_conf CPUID data.

Signed-off-by: default avatarIsaku Yamahata <isaku.yamahata@intel.com>
Co-developed-by: default avatarXiaoyao Li <xiaoyao.li@intel.com>
Signed-off-by: default avatarXiaoyao Li <xiaoyao.li@intel.com>
Co-developed-by: default avatarTony Lindgren <tony.lindgren@linux.intel.com>
Signed-off-by: default avatarTony Lindgren <tony.lindgren@linux.intel.com>
Signed-off-by: default avatarRick Edgecombe <rick.p.edgecombe@intel.com>
Reviewed-by: default avatarBinbin Wu <binbin.wu@linux.intel.com>
---
 - Clarify comment about EAX[23:16] in td_init_cpuid_entry2() (Xiaoyao)
 - Add comment for configurable CPUID bits (Xiaoyao)
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent b2aaf38c

arch/x86/include/uapi/asm/kvm.h

+11 −0
Original line number Diff line number Diff line
@@ -929,6 +929,8 @@ struct kvm_hyperv_eventfd { 


/* Trust Domain eXtension sub-ioctl() commands. */

enum kvm_tdx_cmd_id {

	KVM_TDX_CAPABILITIES = 0,



	KVM_TDX_CMD_NR_MAX,

};
@@ -950,4 +952,13 @@ struct kvm_tdx_cmd { 
	__u64 hw_error;

};



struct kvm_tdx_capabilities {

	__u64 supported_attrs;

	__u64 supported_xfam;

	__u64 reserved[254];



	/* Configurable CPUID bits for userspace */

	struct kvm_cpuid2 cpuid;

};



#endif /* _ASM_X86_KVM_H */

arch/x86/kvm/vmx/tdx.c

+137 −0
Original line number Diff line number Diff line
@@ -33,6 +33,8 @@ static enum cpuhp_state tdx_cpuhp_state; 


static const struct tdx_sys_info *tdx_sysinfo;



#define KVM_SUPPORTED_TD_ATTRS (TDX_TD_ATTR_SEPT_VE_DISABLE)



static __always_inline struct kvm_tdx *to_kvm_tdx(struct kvm *kvm)

{

	return container_of(kvm, struct kvm_tdx, kvm);
@@ -43,6 +45,129 @@ static __always_inline struct vcpu_tdx *to_tdx(struct kvm_vcpu *vcpu) 
	return container_of(vcpu, struct vcpu_tdx, vcpu);

}



static u64 tdx_get_supported_attrs(const struct tdx_sys_info_td_conf *td_conf)

{

	u64 val = KVM_SUPPORTED_TD_ATTRS;



	if ((val & td_conf->attributes_fixed1) != td_conf->attributes_fixed1)

		return 0;



	val &= td_conf->attributes_fixed0;



	return val;

}



static u64 tdx_get_supported_xfam(const struct tdx_sys_info_td_conf *td_conf)

{

	u64 val = kvm_caps.supported_xcr0 | kvm_caps.supported_xss;



	if ((val & td_conf->xfam_fixed1) != td_conf->xfam_fixed1)

		return 0;



	val &= td_conf->xfam_fixed0;



	return val;

}



static u32 tdx_set_guest_phys_addr_bits(const u32 eax, int addr_bits)

{

	return (eax & ~GENMASK(23, 16)) | (addr_bits & 0xff) << 16;

}



#define KVM_TDX_CPUID_NO_SUBLEAF	((__u32)-1)



static void td_init_cpuid_entry2(struct kvm_cpuid_entry2 *entry, unsigned char idx)

{

	const struct tdx_sys_info_td_conf *td_conf = &tdx_sysinfo->td_conf;



	entry->function = (u32)td_conf->cpuid_config_leaves[idx];

	entry->index = td_conf->cpuid_config_leaves[idx] >> 32;

	entry->eax = (u32)td_conf->cpuid_config_values[idx][0];

	entry->ebx = td_conf->cpuid_config_values[idx][0] >> 32;

	entry->ecx = (u32)td_conf->cpuid_config_values[idx][1];

	entry->edx = td_conf->cpuid_config_values[idx][1] >> 32;



	if (entry->index == KVM_TDX_CPUID_NO_SUBLEAF)

		entry->index = 0;



	/*

	 * The TDX module doesn't allow configuring the guest phys addr bits

	 * (EAX[23:16]).  However, KVM uses it as an interface to the userspace

	 * to configure the GPAW.  Report these bits as configurable.

	 */

	if (entry->function == 0x80000008)

		entry->eax = tdx_set_guest_phys_addr_bits(entry->eax, 0xff);

}



static int init_kvm_tdx_caps(const struct tdx_sys_info_td_conf *td_conf,

			     struct kvm_tdx_capabilities *caps)

{

	int i;



	caps->supported_attrs = tdx_get_supported_attrs(td_conf);

	if (!caps->supported_attrs)

		return -EIO;



	caps->supported_xfam = tdx_get_supported_xfam(td_conf);

	if (!caps->supported_xfam)

		return -EIO;



	caps->cpuid.nent = td_conf->num_cpuid_config;



	for (i = 0; i < td_conf->num_cpuid_config; i++)

		td_init_cpuid_entry2(&caps->cpuid.entries[i], i);



	return 0;

}



static int tdx_get_capabilities(struct kvm_tdx_cmd *cmd)

{

	const struct tdx_sys_info_td_conf *td_conf = &tdx_sysinfo->td_conf;

	struct kvm_tdx_capabilities __user *user_caps;

	struct kvm_tdx_capabilities *caps = NULL;

	int ret = 0;



	/* flags is reserved for future use */

	if (cmd->flags)

		return -EINVAL;



	caps = kmalloc(sizeof(*caps) +

		       sizeof(struct kvm_cpuid_entry2) * td_conf->num_cpuid_config,

		       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->cpuid.nent < td_conf->num_cpuid_config) {

		ret = -E2BIG;

		goto out;

	}



	ret = init_kvm_tdx_caps(td_conf, caps);

	if (ret)

		goto out;



	if (copy_to_user(user_caps, caps, sizeof(*caps))) {

		ret = -EFAULT;

		goto out;

	}



	if (copy_to_user(user_caps->cpuid.entries, caps->cpuid.entries,

			 caps->cpuid.nent *

			 sizeof(caps->cpuid.entries[0])))

		ret = -EFAULT;



out:

	/* kfree() accepts NULL. */

	kfree(caps);

	return ret;

}



int tdx_vm_ioctl(struct kvm *kvm, void __user *argp)

{

	struct kvm_tdx_cmd tdx_cmd;
@@ -61,6 +186,9 @@ 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;
@@ -160,11 +288,20 @@ static int __init __tdx_bringup(void) 
		goto get_sysinfo_err;

	}



	/* Check TDX module and KVM capabilities */

	if (!tdx_get_supported_attrs(&tdx_sysinfo->td_conf) ||

	    !tdx_get_supported_xfam(&tdx_sysinfo->td_conf))

		goto get_sysinfo_err;



	if (!(tdx_sysinfo->features.tdx_features0 & MD_FIELD_ID_FEATURES0_TOPOLOGY_ENUM))

		goto get_sysinfo_err;



	/*

	 * Leave hardware virtualization enabled after TDX is enabled

	 * successfully.  TDX CPU hotplug depends on this.

	 */

	return 0;



get_sysinfo_err:

	__tdx_cleanup();

tdx_bringup_err:

arch/x86/kvm/vmx/tdx_arch.h

+2 −0
Original line number Diff line number Diff line
@@ -121,4 +121,6 @@ struct td_params { 
#define TDX_MIN_TSC_FREQUENCY_KHZ		(100 * 1000)

#define TDX_MAX_TSC_FREQUENCY_KHZ		(10 * 1000 * 1000)



#define MD_FIELD_ID_FEATURES0_TOPOLOGY_ENUM	BIT_ULL(20)



#endif /* __KVM_X86_TDX_ARCH_H */