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Subject[RFC Part2 PATCH v3 13/26] KVM: SVM: Add KVM_SEV_INIT command
Date
The command initializes the SEV firmware and allocate a new ASID for
this guest from SEV ASID pool. The firmware must be initialized before
we issue guest launch command to create a new encryption context.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
arch/x86/kvm/svm.c | 188 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 187 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 2a5a03a..e99a572 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -37,6 +37,8 @@
#include <linux/amd-iommu.h>
#include <linux/hashtable.h>
#include <linux/frame.h>
+#include <linux/psp-sev.h>
+#include <linux/file.h>

#include <asm/apic.h>
#include <asm/perf_event.h>
@@ -321,6 +323,14 @@ enum {

/* Secure Encrypted Virtualization */
static unsigned int max_sev_asid;
+static unsigned long *sev_asid_bitmap;
+static int sev_asid_new(void);
+static void sev_asid_free(int asid);
+
+static bool svm_sev_enabled(void)
+{
+ return !!max_sev_asid;
+}

static inline struct kvm_sev_info *to_sev_info(struct kvm *kvm)
{
@@ -1093,6 +1103,12 @@ static __init void sev_hardware_setup(void)
if (!nguests)
return;

+ /* Initialize SEV ASID bitmap */
+ sev_asid_bitmap = kcalloc(BITS_TO_LONGS(nguests),
+ sizeof(unsigned long), GFP_KERNEL);
+ if (IS_ERR(sev_asid_bitmap))
+ return;
+
max_sev_asid = nguests;
}

@@ -1184,10 +1200,18 @@ static __init int svm_hardware_setup(void)
return r;
}

+static __exit void sev_hardware_unsetup(void)
+{
+ kfree(sev_asid_bitmap);
+}
+
static __exit void svm_hardware_unsetup(void)
{
int cpu;

+ if (svm_sev_enabled())
+ sev_hardware_unsetup();
+
for_each_possible_cpu(cpu)
svm_cpu_uninit(cpu);

@@ -1373,6 +1397,9 @@ static void init_vmcb(struct vcpu_svm *svm)
svm->vmcb->control.virt_ext |= VIRTUAL_VMLOAD_VMSAVE_ENABLE_MASK;
}

+ if (sev_guest(svm->vcpu.kvm))
+ svm->vmcb->control.nested_ctl |= SVM_NESTED_CTL_SEV_ENABLE;
+
mark_all_dirty(svm->vmcb);

enable_gif(svm);
@@ -1483,6 +1510,51 @@ static inline int avic_free_vm_id(int id)
return 0;
}

+static int sev_platform_get_state(int *state, int *error)
+{
+ int ret;
+ struct sev_data_status *data;
+
+ data = kzalloc(sizeof(*data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ ret = sev_platform_status(data, error);
+ if (!ret)
+ *state = data->state;
+
+ kfree(data);
+ return ret;
+}
+
+static void sev_firmware_uninit(void)
+{
+ int rc, state, error;
+
+ rc = sev_platform_get_state(&state, &error);
+ if (rc) {
+ pr_err("SEV: failed to get firmware state (%#x)\n",
+ error);
+ return;
+ }
+
+ /* If we are in initialized state then uninitialize it */
+ if (state == SEV_STATE_INIT)
+ sev_platform_shutdown(&error);
+
+}
+
+static void sev_vm_destroy(struct kvm *kvm)
+{
+ int state, error;
+
+ if (!sev_guest(kvm))
+ return;
+
+ sev_asid_free(sev_get_asid(kvm));
+ sev_firmware_uninit();
+}
+
static void avic_vm_destroy(struct kvm *kvm)
{
unsigned long flags;
@@ -1503,6 +1575,12 @@ 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;
@@ -5428,6 +5506,112 @@ static void svm_setup_mce(struct kvm_vcpu *vcpu)
vcpu->arch.mcg_cap &= 0x1ff;
}

+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 pos;
+
+ pos = asid - 1;
+ clear_bit(pos, sev_asid_bitmap);
+}
+
+static int sev_firmware_init(int *error)
+{
+ int ret, state;
+
+ ret = sev_platform_get_state(&state, error);
+ if (ret)
+ return ret;
+
+ /*
+ * If SEV firmware is in uninitialized state, lets initialize the
+ * firmware before issuing guest commands.
+ */
+ if (state == SEV_STATE_UNINIT) {
+ struct sev_data_init *data;
+
+ data = kzalloc(sizeof(*data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ ret = sev_platform_init(data, error);
+ kfree(data);
+ }
+
+ return ret;
+}
+
+static int sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp)
+{
+ int asid, ret;
+ struct fd f;
+
+ f = fdget(argp->sev_fd);
+ if (!f.file)
+ return -EBADF;
+
+ /* initialize the SEV firmware */
+ ret = sev_firmware_init(&argp->error);
+ if (ret)
+ goto e_err;
+
+ /* allocate asid from SEV pool */
+ ret = -ENOTTY;
+ asid = sev_asid_new();
+ if (asid < 0) {
+ pr_err("SEV: failed to get free asid\n");
+ sev_platform_shutdown(&argp->error);
+ goto e_err;
+ }
+
+ sev_set_active(kvm);
+ sev_set_asid(kvm, asid);
+ sev_set_fd(kvm, argp->sev_fd);
+ ret = 0;
+e_err:
+ fdput(f);
+ return ret;
+}
+
+static int svm_memory_encryption_op(struct kvm *kvm, void __user *argp)
+{
+ struct kvm_sev_cmd sev_cmd;
+ int r = -ENOTTY;
+
+ 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_INIT: {
+ r = sev_guest_init(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,
@@ -5444,7 +5628,7 @@ 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,
@@ -5540,6 +5724,8 @@ static struct kvm_x86_ops svm_x86_ops __ro_after_init = {
.deliver_posted_interrupt = svm_deliver_avic_intr,
.update_pi_irte = svm_update_pi_irte,
.setup_mce = svm_setup_mce,
+
+ .memory_encryption_op = svm_memory_encryption_op,
};

static int __init svm_init(void)
--
2.9.4
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