The command is used to bootstrap SEV guest from unencrypted boot images.
The command creates a new VM encryption key (VEK) using the guest owner's
public DH certificates, and session data. The VEK will be used to encrypt
the guest memory.
Signed-off-by: Brijesh Singh <brijesh.singh@xxxxxxx>
---
arch/x86/kvm/svm.c | 302 ++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 301 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index fb63398..b5fa8c0 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -37,6 +37,7 @@
#include <linux/amd-iommu.h>
#include <linux/hashtable.h>
#include <linux/psp-sev.h>
+#include <linux/file.h>
#include <asm/apic.h>
#include <asm/perf_event.h>
@@ -497,6 +498,10 @@ static inline bool gif_set(struct vcpu_svm *svm)
/* Secure Encrypted Virtualization */
static unsigned int max_sev_asid;
static unsigned long *sev_asid_bitmap;
+static void sev_deactivate_handle(struct kvm *kvm);
+static void sev_decommission_handle(struct kvm *kvm);
+static int sev_asid_new(void);
+static void sev_asid_free(int asid);
static bool kvm_sev_enabled(void)
{
@@ -1534,6 +1539,17 @@ static inline int avic_free_vm_id(int id)
return 0;
}
+static void sev_vm_destroy(struct kvm *kvm)
+{
+ if (!sev_guest(kvm))
+ return;
+
+ /* release the firmware resources */
+ sev_deactivate_handle(kvm);
+ sev_decommission_handle(kvm);
+ sev_asid_free(sev_get_asid(kvm));
+}
+
static void avic_vm_destroy(struct kvm *kvm)
{
unsigned long flags;
@@ -1551,6 +1567,12 @@ static void avic_vm_destroy(struct kvm *kvm)
spin_unlock_irqrestore(&svm_vm_data_hash_lock, flags);
}
+static void svm_vm_destroy(struct kvm *kvm)
+{
+ avic_vm_destroy(kvm);
+ sev_vm_destroy(kvm);
+}
+
static int avic_vm_init(struct kvm *kvm)
{
unsigned long flags;
@@ -5502,6 +5524,282 @@ static inline void avic_post_state_restore(struct kvm_vcpu *vcpu)
avic_handle_ldr_update(vcpu);
}
+static int sev_asid_new(void)
+{
+ int pos;
+
+ if (!max_sev_asid)
+ return -EINVAL;
+
+ pos = find_first_zero_bit(sev_asid_bitmap, max_sev_asid);
+ if (pos >= max_sev_asid)
+ return -EBUSY;
+
+ set_bit(pos, sev_asid_bitmap);
+ return pos + 1;
+}
+
+static void sev_asid_free(int asid)
+{
+ int cpu, pos;
+ struct svm_cpu_data *sd;
+
+ pos = asid - 1;
+ clear_bit(pos, sev_asid_bitmap);
+
+ for_each_possible_cpu(cpu) {
+ sd = per_cpu(svm_data, cpu);
+ sd->sev_vmcbs[pos] = NULL;
+ }
+}
+
+static int sev_issue_cmd(struct kvm *kvm, int id, void *data, int *error)
+{
+ int ret;
+ struct fd f;
+ int fd = sev_get_fd(kvm);
+
+ f = fdget(fd);
+ if (!f.file)
+ return -EBADF;
+
+ ret = sev_issue_cmd_external_user(f.file, id, data, 0, error);
+ fdput(f);
+
+ return ret;
+}
+
+static void sev_decommission_handle(struct kvm *kvm)
+{
+ int ret, error;
+ struct sev_data_decommission *data;
+
+ data = kzalloc(sizeof(*data), GFP_KERNEL);
+ if (!data)
+ return;
+
+ data->handle = sev_get_handle(kvm);
+ ret = sev_guest_decommission(data, &error);
+ if (ret)
+ pr_err("SEV: DECOMMISSION %d (%#x)\n", ret, error);
+
+ kfree(data);
+}
+
+static void sev_deactivate_handle(struct kvm *kvm)
+{
+ int ret, error;
+ struct sev_data_deactivate *data;
+
+ data = kzalloc(sizeof(*data), GFP_KERNEL);
+ if (!data)
+ return;
+
+ data->handle = sev_get_handle(kvm);
+ ret = sev_guest_deactivate(data, &error);
+ if (ret) {
+ pr_err("SEV: DEACTIVATE %d (%#x)\n", ret, error);
+ goto buffer_free;
+ }
+
+ wbinvd_on_all_cpus();
+
+ ret = sev_guest_df_flush(&error);
+ if (ret)
+ pr_err("SEV: DF_FLUSH %d (%#x)\n", ret, error);
+
+buffer_free:
+ kfree(data);
+}
+
+static int sev_activate_asid(unsigned int handle, int asid, int *error)
+{
+ int ret;
+ struct sev_data_activate *data;
+
+ wbinvd_on_all_cpus();
+
+ ret = sev_guest_df_flush(error);
+ if (ret) {
+ pr_err("SEV: DF_FLUSH %d (%#x)\n", ret, *error);
+ return ret;
+ }
+
+ data = kzalloc(sizeof(*data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ data->handle = handle;
+ data->asid = asid;
+ ret = sev_guest_activate(data, error);
+ if (ret)
+ pr_err("SEV: ACTIVATE %d (%#x)\n", ret, *error);
+
+ kfree(data);
+ return ret;
+}
+
+static int sev_pre_start(struct kvm *kvm, int *asid)
+{
+ int ret;
+
+ /* If guest has active SEV handle then deactivate before creating the
+ * encryption context.
+ */
+ if (sev_guest(kvm)) {
+ sev_deactivate_handle(kvm);
+ sev_decommission_handle(kvm);
+ *asid = sev_get_asid(kvm); /* reuse the asid */
+ ret = 0;
+ } else {
+ /* Allocate new asid for this launch */
+ ret = sev_asid_new();
+ if (ret < 0) {
+ pr_err("SEV: failed to get free asid\n");
+ return ret;
+ }
+ *asid = ret;
+ ret = 0;
+ }
+
+ return ret;
+}
+
+static int sev_post_start(struct kvm *kvm, int asid, int handle,
+ int sev_fd, int *error)
+{
+ int ret;
+
+ /* activate asid */
+ ret = sev_activate_asid(handle, asid, error);
+ if (ret)
+ return ret;
+
+ kvm->arch.sev_info.handle = handle;
+ kvm->arch.sev_info.asid = asid;
+ kvm->arch.sev_info.sev_fd = sev_fd;
+
+ return 0;
+}
+
+static int sev_launch_start(struct kvm *kvm, struct kvm_sev_cmd *argp)
+{
+ int ret, asid = 0;
+ void *dh_cert_addr = NULL;
+ void *session_addr = NULL;
+ struct kvm_sev_launch_start params;
+ struct sev_data_launch_start *start;
+ int *error = &argp->error;
+ struct fd f;
+
+ f = fdget(argp->sev_fd);
+ if (!f.file)
+ return -EBADF;
+
+ /* Get parameter from the user */
+ ret = -EFAULT;
+ if (copy_from_user(¶ms, (void *)argp->data,
+ sizeof(struct kvm_sev_launch_start)))
+ goto err_1;
+
+ ret = -ENOMEM;
+ start = kzalloc(sizeof(*start), GFP_KERNEL);
+ if (!start)
+ goto err_1;
+
+ ret = sev_pre_start(kvm, &asid);
+ if (ret)
+ goto err_2;
+
+ start->handle = params.handle;
+ start->policy = params.policy;
+
+ /* Copy DH certificate from userspace */
+ if (params.dh_cert_length && params.dh_cert_data) {
+ dh_cert_addr = kmalloc(params.dh_cert_length, GFP_KERNEL);
+ if (!dh_cert_addr) {
+ ret = -EFAULT;
+ goto err_3;
+ }
+ if (copy_from_user(dh_cert_addr, (void *)params.dh_cert_data,
+ params.dh_cert_length)) {
+ ret = -EFAULT;
+ goto err_3;
+ }
+
+ start->dh_cert_address = __psp_pa(dh_cert_addr);
+ start->dh_cert_length = params.dh_cert_length;
+ }
+
+ /* Copy session data from userspace */
+ if (params.session_length && params.session_data) {
+ session_addr = kmalloc(params.dh_cert_length, GFP_KERNEL);
+ if (!session_addr) {
+ ret = -EFAULT;
+ goto err_3;
+ }
+ if (copy_from_user(session_addr, (void *)params.session_data,
+ params.session_length)) {
+ ret = -EFAULT;
+ goto err_3;
+ }
+ start->session_data_address = __psp_pa(session_addr);
+ start->session_data_length = params.session_length;
+ }
+
+ /* launch start */
+ ret = sev_issue_cmd_external_user(f.file, SEV_CMD_LAUNCH_START,
+ start, 0, error);
+ if (ret) {
+ pr_err("SEV: LAUNCH_START ret=%d (%#010x)\n", ret, *error);
+ goto err_3;
+ }
+
+ ret = sev_post_start(kvm, asid, start->handle, argp->sev_fd, error);
+ if (ret)
+ goto err_3;
+
+ params.handle = start->handle;
+ if (copy_to_user((void *) argp->data, ¶ms,
+ sizeof(struct kvm_sev_launch_start)))
+ ret = -EFAULT;
+err_3:
+ if (ret && asid) /* free asid if we have encountered error */
+ sev_asid_free(asid);
+ kfree(dh_cert_addr);
+ kfree(session_addr);
+err_2:
+ kfree(start);
+err_1:
+ fdput(f);
+ return ret;
+}
+
+static int amd_memory_encryption_cmd(struct kvm *kvm, void __user *argp)
+{
+ int r = -ENOTTY;
+ struct kvm_sev_cmd sev_cmd;
+
+ if (copy_from_user(&sev_cmd, argp, sizeof(struct kvm_sev_cmd)))
+ return -EFAULT;
+
+ mutex_lock(&kvm->lock);
+
+ switch (sev_cmd.id) {
+ case KVM_SEV_LAUNCH_START: {
+ r = sev_launch_start(kvm, &sev_cmd);
+ break;
+ }
+ default:
+ break;
+ }
+
+ mutex_unlock(&kvm->lock);
+ if (copy_to_user(argp, &sev_cmd, sizeof(struct kvm_sev_cmd)))
+ r = -EFAULT;
+ return r;
+}
+
static struct kvm_x86_ops svm_x86_ops __ro_after_init = {
.cpu_has_kvm_support = has_svm,
.disabled_by_bios = is_disabled,
@@ -5518,7 +5816,7 @@ static struct kvm_x86_ops svm_x86_ops __ro_after_init = {
.vcpu_reset = svm_vcpu_reset,
.vm_init = avic_vm_init,
- .vm_destroy = avic_vm_destroy,
+ .vm_destroy = svm_vm_destroy,
.prepare_guest_switch = svm_prepare_guest_switch,
.vcpu_load = svm_vcpu_load,
@@ -5617,6 +5915,8 @@ static struct kvm_x86_ops svm_x86_ops __ro_after_init = {
.pmu_ops = &amd_pmu_ops,
.deliver_posted_interrupt = svm_deliver_avic_intr,
.update_pi_irte = svm_update_pi_irte,
+
+ .memory_encryption_op = amd_memory_encryption_cmd,
};
static int __init svm_init(void)
