KVM: SEV: Add KVM_SEV_SNP_LAUNCH_START command (136d8bc9) · Commits · git / linux-net

Documentation/virt/kvm/x86/amd-memory-encryption.rst

+27 −1

Original line number	Diff line number	Diff line
		@@ -466,6 +466,30 @@ issued by the hypervisor to make the guest ready for execution.

		Returns: 0 on success, -negative on error

		18. KVM_SEV_SNP_LAUNCH_START
		----------------------------

		The KVM_SNP_LAUNCH_START command is used for creating the memory encryption
		context for the SEV-SNP guest. It must be called prior to issuing
		KVM_SEV_SNP_LAUNCH_UPDATE or KVM_SEV_SNP_LAUNCH_FINISH;

		Parameters (in): struct kvm_sev_snp_launch_start

		Returns: 0 on success, -negative on error

		::

		struct kvm_sev_snp_launch_start {
		__u64 policy; /* Guest policy to use. */
		__u8 gosvw[16]; /* Guest OS visible workarounds. */
		__u16 flags; /* Must be zero. */
		__u8 pad0[6];
		__u64 pad1[4];
		};

		See SNP_LAUNCH_START in the SEV-SNP specification [snp-fw-abi]_ for further
		details on the input parameters in ``struct kvm_sev_snp_launch_start``.

		Device attribute API
		====================

		@@ -497,9 +521,11 @@ References
		==========


		See [white-paper]_, [api-spec]_, [amd-apm]_ and [kvm-forum]_ for more info.
		See [white-paper]_, [api-spec]_, [amd-apm]_, [kvm-forum]_, and [snp-fw-abi]_
		for more info.

		.. [white-paper] https://developer.amd.com/wordpress/media/2013/12/AMD_Memory_Encryption_Whitepaper_v7-Public.pdf
		.. [api-spec] https://support.amd.com/TechDocs/55766_SEV-KM_API_Specification.pdf
		.. [amd-apm] https://support.amd.com/TechDocs/24593.pdf (section 15.34)
		.. [kvm-forum] https://www.linux-kvm.org/images/7/74/02x08A-Thomas_Lendacky-AMDs_Virtualizatoin_Memory_Encryption_Technology.pdf
		.. [snp-fw-abi] https://www.amd.com/system/files/TechDocs/56860.pdf

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

+11 −0

Original line number	Diff line number	Diff line
		@@ -697,6 +697,9 @@ enum sev_cmd_id {
		/* Second time is the charm; improved versions of the above ioctls. */
		KVM_SEV_INIT2,

		/* SNP-specific commands */
		KVM_SEV_SNP_LAUNCH_START = 100,

		KVM_SEV_NR_MAX,
		};

		@@ -824,6 +827,14 @@ struct kvm_sev_receive_update_data {
		__u32 pad2;
		};

		struct kvm_sev_snp_launch_start {
		__u64 policy;
		__u8 gosvw[16];
		__u16 flags;
		__u8 pad0[6];
		__u64 pad1[4];
		};

		#define KVM_X2APIC_API_USE_32BIT_IDS (1ULL << 0)
		#define KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK (1ULL << 1)

arch/x86/kvm/svm/sev.c

+173 −3

Original line number	Diff line number	Diff line
		@@ -25,6 +25,7 @@
		#include <asm/fpu/xcr.h>
		#include <asm/fpu/xstate.h>
		#include <asm/debugreg.h>
		#include <asm/sev.h>

		#include "mmu.h"
		#include "x86.h"
		@@ -59,6 +60,21 @@ static u64 sev_supported_vmsa_features;
		#define AP_RESET_HOLD_NAE_EVENT 1
		#define AP_RESET_HOLD_MSR_PROTO 2

		/* As defined by SEV-SNP Firmware ABI, under "Guest Policy". */
		#define SNP_POLICY_MASK_API_MINOR GENMASK_ULL(7, 0)
		#define SNP_POLICY_MASK_API_MAJOR GENMASK_ULL(15, 8)
		#define SNP_POLICY_MASK_SMT BIT_ULL(16)
		#define SNP_POLICY_MASK_RSVD_MBO BIT_ULL(17)
		#define SNP_POLICY_MASK_DEBUG BIT_ULL(19)
		#define SNP_POLICY_MASK_SINGLE_SOCKET BIT_ULL(20)

		#define SNP_POLICY_MASK_VALID (SNP_POLICY_MASK_API_MINOR \| \
		SNP_POLICY_MASK_API_MAJOR \| \
		SNP_POLICY_MASK_SMT \| \
		SNP_POLICY_MASK_RSVD_MBO \| \
		SNP_POLICY_MASK_DEBUG \| \
		SNP_POLICY_MASK_SINGLE_SOCKET)

		static u8 sev_enc_bit;
		static DECLARE_RWSEM(sev_deactivate_lock);
		static DEFINE_MUTEX(sev_bitmap_lock);
		@@ -69,6 +85,8 @@ static unsigned int nr_asids;
		static unsigned long *sev_asid_bitmap;
		static unsigned long *sev_reclaim_asid_bitmap;

		static int snp_decommission_context(struct kvm *kvm);

		struct enc_region {
		struct list_head list;
		unsigned long npages;
		@@ -95,12 +113,17 @@ static int sev_flush_asids(unsigned int min_asid, unsigned int max_asid)
		down_write(&sev_deactivate_lock);

		wbinvd_on_all_cpus();

		if (sev_snp_enabled)
		ret = sev_do_cmd(SEV_CMD_SNP_DF_FLUSH, NULL, &error);
		else
		ret = sev_guest_df_flush(&error);

		up_write(&sev_deactivate_lock);

		if (ret)
		pr_err("SEV: DF_FLUSH failed, ret=%d, error=%#x\n", ret, error);
		pr_err("SEV%s: DF_FLUSH failed, ret=%d, error=%#x\n",
		sev_snp_enabled ? "-SNP" : "", ret, error);

		return ret;
		}
		@@ -1998,6 +2021,106 @@ int sev_dev_get_attr(u32 group, u64 attr, u64 *val)
		}
		}

		/*
		* The guest context contains all the information, keys and metadata
		* associated with the guest that the firmware tracks to implement SEV
		* and SNP features. The firmware stores the guest context in hypervisor
		* provide page via the SNP_GCTX_CREATE command.
		*/
		static void snp_context_create(struct kvm kvm, struct kvm_sev_cmd *argp)
		{
		struct sev_data_snp_addr data = {};
		void *context;
		int rc;

		/* Allocate memory for context page */
		context = snp_alloc_firmware_page(GFP_KERNEL_ACCOUNT);
		if (!context)
		return NULL;

		data.address = __psp_pa(context);
		rc = __sev_issue_cmd(argp->sev_fd, SEV_CMD_SNP_GCTX_CREATE, &data, &argp->error);
		if (rc) {
		pr_warn("Failed to create SEV-SNP context, rc %d fw_error %d",
		rc, argp->error);
		snp_free_firmware_page(context);
		return NULL;
		}

		return context;
		}

		static int snp_bind_asid(struct kvm kvm, int error)
		{
		struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
		struct sev_data_snp_activate data = {0};

		data.gctx_paddr = __psp_pa(sev->snp_context);
		data.asid = sev_get_asid(kvm);
		return sev_issue_cmd(kvm, SEV_CMD_SNP_ACTIVATE, &data, error);
		}

		static int snp_launch_start(struct kvm kvm, struct kvm_sev_cmd argp)
		{
		struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
		struct sev_data_snp_launch_start start = {0};
		struct kvm_sev_snp_launch_start params;
		int rc;

		if (!sev_snp_guest(kvm))
		return -ENOTTY;

		if (copy_from_user(&params, u64_to_user_ptr(argp->data), sizeof(params)))
		return -EFAULT;

		/* Don't allow userspace to allocate memory for more than 1 SNP context. */
		if (sev->snp_context)
		return -EINVAL;

		sev->snp_context = snp_context_create(kvm, argp);
		if (!sev->snp_context)
		return -ENOTTY;

		if (params.flags)
		return -EINVAL;

		if (params.policy & ~SNP_POLICY_MASK_VALID)
		return -EINVAL;

		/* Check for policy bits that must be set */
		if (!(params.policy & SNP_POLICY_MASK_RSVD_MBO) \|\|
		!(params.policy & SNP_POLICY_MASK_SMT))
		return -EINVAL;

		if (params.policy & SNP_POLICY_MASK_SINGLE_SOCKET)
		return -EINVAL;

		start.gctx_paddr = __psp_pa(sev->snp_context);
		start.policy = params.policy;
		memcpy(start.gosvw, params.gosvw, sizeof(params.gosvw));
		rc = __sev_issue_cmd(argp->sev_fd, SEV_CMD_SNP_LAUNCH_START, &start, &argp->error);
		if (rc) {
		pr_debug("%s: SEV_CMD_SNP_LAUNCH_START firmware command failed, rc %d\n",
		__func__, rc);
		goto e_free_context;
		}

		sev->fd = argp->sev_fd;
		rc = snp_bind_asid(kvm, &argp->error);
		if (rc) {
		pr_debug("%s: Failed to bind ASID to SEV-SNP context, rc %d\n",
		__func__, rc);
		goto e_free_context;
		}

		return 0;

		e_free_context:
		snp_decommission_context(kvm);

		return rc;
		}

		int sev_mem_enc_ioctl(struct kvm kvm, void __user argp)
		{
		struct kvm_sev_cmd sev_cmd;
		@@ -2021,6 +2144,15 @@ int sev_mem_enc_ioctl(struct kvm kvm, void __user argp)
		goto out;
		}

		/*
		* Once KVM_SEV_INIT2 initializes a KVM instance as an SNP guest, only
		* allow the use of SNP-specific commands.
		*/
		if (sev_snp_guest(kvm) && sev_cmd.id < KVM_SEV_SNP_LAUNCH_START) {
		r = -EPERM;
		goto out;
		}

		switch (sev_cmd.id) {
		case KVM_SEV_ES_INIT:
		if (!sev_es_enabled) {
		@@ -2085,6 +2217,9 @@ int sev_mem_enc_ioctl(struct kvm kvm, void __user argp)
		case KVM_SEV_RECEIVE_FINISH:
		r = sev_receive_finish(kvm, &sev_cmd);
		break;
		case KVM_SEV_SNP_LAUNCH_START:
		r = snp_launch_start(kvm, &sev_cmd);
		break;
		default:
		r = -EINVAL;
		goto out;
		@@ -2280,6 +2415,31 @@ int sev_vm_copy_enc_context_from(struct kvm *kvm, unsigned int source_fd)
		return ret;
		}

		static int snp_decommission_context(struct kvm *kvm)
		{
		struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
		struct sev_data_snp_addr data = {};
		int ret;

		/* If context is not created then do nothing */
		if (!sev->snp_context)
		return 0;

		/* Do the decommision, which will unbind the ASID from the SNP context */
		data.address = __sme_pa(sev->snp_context);
		down_write(&sev_deactivate_lock);
		ret = sev_do_cmd(SEV_CMD_SNP_DECOMMISSION, &data, NULL);
		up_write(&sev_deactivate_lock);

		if (WARN_ONCE(ret, "Failed to release guest context, ret %d", ret))
		return ret;

		snp_free_firmware_page(sev->snp_context);
		sev->snp_context = NULL;

		return 0;
		}

		void sev_vm_destroy(struct kvm *kvm)
		{
		struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
		@@ -2321,7 +2481,17 @@ void sev_vm_destroy(struct kvm *kvm)
		}
		}

		if (sev_snp_guest(kvm)) {
		/*
		* Decomission handles unbinding of the ASID. If it fails for
		* some unexpected reason, just leak the ASID.
		*/
		if (snp_decommission_context(kvm))
		return;
		} else {
		sev_unbind_asid(kvm, sev->handle);
		}

		sev_asid_free(sev);
		}

arch/x86/kvm/svm/svm.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -93,6 +93,7 @@ struct kvm_sev_info {
		struct list_head mirror_entry; /* Use as a list entry of mirrors */
		struct misc_cg misc_cg; / For misc cgroup accounting */
		atomic_t migration_in_progress;
		void snp_context; / SNP guest context page */
		};

		struct kvm_svm {