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Date: Wed, 14 Dec 2022 13:40:30 -0600
From: Michael Roth <michael.roth@....com>
To: <kvm@...r.kernel.org>
CC: <linux-coco@...ts.linux.dev>, <linux-mm@...ck.org>,
<linux-crypto@...r.kernel.org>, <x86@...nel.org>,
<linux-kernel@...r.kernel.org>, <tglx@...utronix.de>,
<mingo@...hat.com>, <jroedel@...e.de>, <thomas.lendacky@....com>,
<hpa@...or.com>, <ardb@...nel.org>, <pbonzini@...hat.com>,
<seanjc@...gle.com>, <vkuznets@...hat.com>,
<wanpengli@...cent.com>, <jmattson@...gle.com>, <luto@...nel.org>,
<dave.hansen@...ux.intel.com>, <slp@...hat.com>,
<pgonda@...gle.com>, <peterz@...radead.org>,
<srinivas.pandruvada@...ux.intel.com>, <rientjes@...gle.com>,
<dovmurik@...ux.ibm.com>, <tobin@....com>, <bp@...en8.de>,
<vbabka@...e.cz>, <kirill@...temov.name>, <ak@...ux.intel.com>,
<tony.luck@...el.com>, <marcorr@...gle.com>,
<sathyanarayanan.kuppuswamy@...ux.intel.com>,
<alpergun@...gle.com>, <dgilbert@...hat.com>, <jarkko@...nel.org>,
<ashish.kalra@....com>, <harald@...fian.com>,
Brijesh Singh <brijesh.singh@....com>
Subject: [PATCH RFC v7 38/64] KVM: SVM: Add KVM_SEV_SNP_LAUNCH_START command
From: Brijesh Singh <brijesh.singh@....com>
KVM_SEV_SNP_LAUNCH_START begins the launch process for an SEV-SNP guest.
The command initializes a cryptographic digest context used to construct
the measurement of the guest. If the guest is expected to be migrated,
the command also binds a migration agent (MA) to the guest.
For more information see the SEV-SNP specification.
Signed-off-by: Brijesh Singh <brijesh.singh@....com>
Signed-off-by: Ashish Kalra <ashish.kalra@....com>
Signed-off-by: Michael Roth <michael.roth@....com>
---
.../virt/kvm/x86/amd-memory-encryption.rst | 24 ++++
arch/x86/kvm/svm/sev.c | 121 +++++++++++++++++-
arch/x86/kvm/svm/svm.h | 1 +
include/uapi/linux/kvm.h | 10 ++
4 files changed, 153 insertions(+), 3 deletions(-)
diff --git a/Documentation/virt/kvm/x86/amd-memory-encryption.rst b/Documentation/virt/kvm/x86/amd-memory-encryption.rst
index 2432213bd0ea..58971fc02a15 100644
--- a/Documentation/virt/kvm/x86/amd-memory-encryption.rst
+++ b/Documentation/virt/kvm/x86/amd-memory-encryption.rst
@@ -461,6 +461,30 @@ The flags bitmap is defined as::
If the specified flags is not supported then return -EOPNOTSUPP, and the supported
flags are returned.
+19. KVM_SNP_LAUNCH_START
+------------------------
+
+The KVM_SNP_LAUNCH_START command is used for creating the memory encryption
+context for the SEV-SNP guest. To create the encryption context, user must
+provide a guest policy, migration agent (if any) and guest OS visible
+workarounds value as defined SEV-SNP specification.
+
+Parameters (in): struct kvm_snp_launch_start
+
+Returns: 0 on success, -negative on error
+
+::
+
+ struct kvm_sev_snp_launch_start {
+ __u64 policy; /* Guest policy to use. */
+ __u64 ma_uaddr; /* userspace address of migration agent */
+ __u8 ma_en; /* 1 if the migration agent is enabled */
+ __u8 imi_en; /* set IMI to 1. */
+ __u8 gosvw[16]; /* guest OS visible workarounds */
+ };
+
+See the SEV-SNP specification for further detail on the launch input.
+
References
==========
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index e3f857cde8c0..6d1d0e424f76 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -21,6 +21,7 @@
#include <asm/pkru.h>
#include <asm/trapnr.h>
#include <asm/fpu/xcr.h>
+#include <asm/sev.h>
#include "mmu.h"
#include "x86.h"
@@ -74,6 +75,8 @@ 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;
@@ -99,12 +102,17 @@ static int sev_flush_asids(int min_asid, int max_asid)
down_write(&sev_deactivate_lock);
wbinvd_on_all_cpus();
- ret = sev_guest_df_flush(&error);
+
+ 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;
}
@@ -2003,6 +2011,80 @@ int sev_vm_move_enc_context_from(struct kvm *kvm, unsigned int source_fd)
return ret;
}
+/*
+ * 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.gctx_paddr = __psp_pa(context);
+ rc = __sev_issue_cmd(argp->sev_fd, SEV_CMD_SNP_GCTX_CREATE, &data, &argp->error);
+ if (rc) {
+ 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(¶ms, (void __user *)(uintptr_t)argp->data, sizeof(params)))
+ return -EFAULT;
+
+ sev->snp_context = snp_context_create(kvm, argp);
+ if (!sev->snp_context)
+ return -ENOTTY;
+
+ 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)
+ goto e_free_context;
+
+ sev->fd = argp->sev_fd;
+ rc = snp_bind_asid(kvm, &argp->error);
+ if (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;
@@ -2093,6 +2175,9 @@ 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;
@@ -2284,6 +2369,28 @@ 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;
+
+ data.gctx_paddr = __sme_pa(sev->snp_context);
+ ret = sev_do_cmd(SEV_CMD_SNP_DECOMMISSION, &data, NULL);
+ if (WARN_ONCE(ret, "failed to release guest context"))
+ return ret;
+
+ /* free the context page now */
+ 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;
@@ -2325,7 +2432,15 @@ void sev_vm_destroy(struct kvm *kvm)
}
}
- sev_unbind_asid(kvm, sev->handle);
+ if (sev_snp_guest(kvm)) {
+ if (snp_decommission_context(kvm)) {
+ WARN_ONCE(1, "Failed to free SNP guest context, leaking asid!\n");
+ return;
+ }
+ } else {
+ sev_unbind_asid(kvm, sev->handle);
+ }
+
sev_asid_free(sev);
}
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 379b253d2464..17200c1ad20e 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -99,6 +99,7 @@ struct kvm_sev_info {
struct misc_cg *misc_cg; /* For misc cgroup accounting */
atomic_t migration_in_progress;
u64 snp_init_flags;
+ void *snp_context; /* SNP guest context page */
};
struct kvm_svm {
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index a6c73297a62d..b2311e0abeef 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -1940,6 +1940,7 @@ enum sev_cmd_id {
/* SNP specific commands */
KVM_SEV_SNP_INIT,
+ KVM_SEV_SNP_LAUNCH_START,
KVM_SEV_NR_MAX,
};
@@ -2047,6 +2048,15 @@ struct kvm_snp_init {
__u64 flags;
};
+struct kvm_sev_snp_launch_start {
+ __u64 policy;
+ __u64 ma_uaddr;
+ __u8 ma_en;
+ __u8 imi_en;
+ __u8 gosvw[16];
+ __u8 pad[6];
+};
+
#define KVM_DEV_ASSIGN_ENABLE_IOMMU (1 << 0)
#define KVM_DEV_ASSIGN_PCI_2_3 (1 << 1)
#define KVM_DEV_ASSIGN_MASK_INTX (1 << 2)
--
2.25.1
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