diff mbox series

[v5,09/10] KVM: SVM: Use new ccp GCTX API

Message ID 20241107232457.4059785-10-dionnaglaze@google.com (mailing list archive)
State New
Headers show
Series [v5,01/10] KVM: SVM: Fix gctx page leak on invalid inputs | expand

Commit Message

Dionna Amalie Glaze Nov. 7, 2024, 11:24 p.m. UTC
Guest context pages should be near 1-to-1 with allocated ASIDs. With the
GCTX API, the ccp driver is better able to associate guest context pages
with the ASID that is/will be bound to it.

This is important to the firmware hotloading implementation to not
corrupt any running VM's guest context page before userspace commits a
new firmware.

CC: Sean Christopherson <seanjc@google.com>
CC: Paolo Bonzini <pbonzini@redhat.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Ingo Molnar <mingo@redhat.com>
CC: Borislav Petkov <bp@alien8.de>
CC: Dave Hansen <dave.hansen@linux.intel.com>
CC: Ashish Kalra <ashish.kalra@amd.com>
CC: Tom Lendacky <thomas.lendacky@amd.com>
CC: John Allen <john.allen@amd.com>
CC: Herbert Xu <herbert@gondor.apana.org.au>
CC: "David S. Miller" <davem@davemloft.net>
CC: Michael Roth <michael.roth@amd.com>
CC: Luis Chamberlain <mcgrof@kernel.org>
CC: Russ Weight <russ.weight@linux.dev>
CC: Danilo Krummrich <dakr@redhat.com>
CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CC: "Rafael J. Wysocki" <rafael@kernel.org>
CC: Tianfei zhang <tianfei.zhang@intel.com>
CC: Alexey Kardashevskiy <aik@amd.com>

Signed-off-by: Dionna Glaze <dionnaglaze@google.com>
---
 arch/x86/kvm/svm/sev.c | 74 ++++++++++++------------------------------
 1 file changed, 20 insertions(+), 54 deletions(-)
diff mbox series

Patch

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index cea41b8cdabe4..d7cef84750b33 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -89,7 +89,7 @@  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);
+static int kvm_decommission_snp_context(struct kvm *kvm);
 
 struct enc_region {
 	struct list_head list;
@@ -2168,51 +2168,12 @@  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 ERR_PTR(-ENOMEM);
-
-	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 ERR_PTR(rc);
-	}
-
-	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;
+	int rc, asid;
 
 	if (!sev_snp_guest(kvm))
 		return -ENOTTY;
@@ -2238,14 +2199,19 @@  static int snp_launch_start(struct kvm *kvm, struct kvm_sev_cmd *argp)
 	if (params.policy & SNP_POLICY_MASK_SINGLE_SOCKET)
 		return -EINVAL;
 
-	sev->snp_context = snp_context_create(kvm, argp);
+	rc = sev_check_external_user(argp->sev_fd);
+	if (rc)
+		return rc;
+
+	asid = sev_get_asid(kvm);
+	sev->snp_context = sev_snp_create_context(asid, &argp->error);
 	if (IS_ERR(sev->snp_context))
 		return PTR_ERR(sev->snp_context);
 
 	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);
+	rc = sev_do_cmd(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);
@@ -2253,7 +2219,7 @@  static int snp_launch_start(struct kvm *kvm, struct kvm_sev_cmd *argp)
 	}
 
 	sev->fd = argp->sev_fd;
-	rc = snp_bind_asid(kvm, &argp->error);
+	rc = sev_snp_activate_asid(asid, &argp->error);
 	if (rc) {
 		pr_debug("%s: Failed to bind ASID to SEV-SNP context, rc %d\n",
 			 __func__, rc);
@@ -2263,7 +2229,7 @@  static int snp_launch_start(struct kvm *kvm, struct kvm_sev_cmd *argp)
 	return 0;
 
 e_free_context:
-	snp_decommission_context(kvm);
+	kvm_decommission_snp_context(kvm);
 
 	return rc;
 }
@@ -2874,26 +2840,26 @@  int sev_vm_copy_enc_context_from(struct kvm *kvm, unsigned int source_fd)
 	return ret;
 }
 
-static int snp_decommission_context(struct kvm *kvm)
+static int kvm_decommission_snp_context(struct kvm *kvm)
 {
 	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
-	struct sev_data_snp_addr data = {};
-	int ret;
+	int ret, error;
 
 	/* 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);
+	/*
+	 * Do the decommision, which will unbind the ASID from the SNP context
+	 * and free the context page.
+	 */
 	down_write(&sev_deactivate_lock);
-	ret = sev_do_cmd(SEV_CMD_SNP_DECOMMISSION, &data, NULL);
+	ret = sev_snp_guest_decommission(sev->asid, &error);
 	up_write(&sev_deactivate_lock);
 
-	if (WARN_ONCE(ret, "Failed to release guest context, ret %d", ret))
+	if (WARN_ONCE(ret, "Failed to release guest context, ret %d fw err %d", ret, error))
 		return ret;
 
-	snp_free_firmware_page(sev->snp_context);
 	sev->snp_context = NULL;
 
 	return 0;
@@ -2947,7 +2913,7 @@  void sev_vm_destroy(struct kvm *kvm)
 		 * Decomission handles unbinding of the ASID. If it fails for
 		 * some unexpected reason, just leak the ASID.
 		 */
-		if (snp_decommission_context(kvm))
+		if (kvm_decommission_snp_context(kvm))
 			return;
 	} else {
 		sev_unbind_asid(kvm, sev->handle);