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Subject[Part2 PATCH v9 25/38] KVM: SVM: Add KVM_SEV_INIT command
Date
The command initializes the SEV platform context and allocates a new ASID
for this guest from the SEV ASID pool. The firmware must be initialized
before we issue any guest launch commands to create a new memory encryption
context.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: x86@kernel.org
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Reviewed-by: Borislav Petkov <bp@suse.de>
---
arch/x86/include/asm/kvm_host.h | 7 +++
arch/x86/kvm/svm.c | 132 +++++++++++++++++++++++++++++++++++++++-
2 files changed, 138 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 58b7cc30466b..384dcfda43cc 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -747,6 +747,11 @@ enum kvm_irqchip_mode {
KVM_IRQCHIP_SPLIT, /* created with KVM_CAP_SPLIT_IRQCHIP */
};

+struct kvm_sev_info {
+ bool active; /* SEV enabled guest */
+ unsigned int asid; /* ASID used for this guest */
+};
+
struct kvm_arch {
unsigned int n_used_mmu_pages;
unsigned int n_requested_mmu_pages;
@@ -834,6 +839,8 @@ struct kvm_arch {

bool x2apic_format;
bool x2apic_broadcast_quirk_disabled;
+
+ struct kvm_sev_info sev_info;
};

struct kvm_vm_stat {
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index ca63642517a7..51186107eb22 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -38,6 +38,7 @@
#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>
@@ -325,6 +326,20 @@ enum {
#define VMCB_AVIC_APIC_BAR_MASK 0xFFFFFFFFFF000ULL

static unsigned int max_sev_asid;
+static unsigned int min_sev_asid;
+static unsigned long *sev_asid_bitmap;
+
+static inline bool svm_sev_enabled(void)
+{
+ return max_sev_asid;
+}
+
+static inline bool sev_guest(struct kvm *kvm)
+{
+ struct kvm_sev_info *sev = &kvm->arch.sev_info;
+
+ return sev->active;
+}

static inline void mark_all_dirty(struct vmcb *vmcb)
{
@@ -1065,6 +1080,15 @@ static __init int sev_hardware_setup(void)
if (!max_sev_asid)
return 1;

+ /* Minimum ASID value that should be used for SEV guest */
+ min_sev_asid = cpuid_edx(0x8000001F);
+
+ /* Initialize SEV ASID bitmap */
+ sev_asid_bitmap = kcalloc(BITS_TO_LONGS(max_sev_asid),
+ sizeof(unsigned long), GFP_KERNEL);
+ if (!sev_asid_bitmap)
+ return 1;
+
status = kmalloc(sizeof(*status), GFP_KERNEL);
if (!status)
return 1;
@@ -1194,6 +1218,9 @@ static __exit void svm_hardware_unsetup(void)
{
int cpu;

+ if (svm_sev_enabled())
+ kfree(sev_asid_bitmap);
+
for_each_possible_cpu(cpu)
svm_cpu_uninit(cpu);

@@ -1384,6 +1411,9 @@ static void init_vmcb(struct vcpu_svm *svm)
svm->vmcb->control.int_ctl |= V_GIF_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);
@@ -1466,6 +1496,29 @@ static int avic_init_backing_page(struct kvm_vcpu *vcpu)
return 0;
}

+static void __sev_asid_free(int asid)
+{
+ int pos;
+
+ pos = asid - 1;
+ clear_bit(pos, sev_asid_bitmap);
+}
+
+static void sev_asid_free(struct kvm *kvm)
+{
+ struct kvm_sev_info *sev = &kvm->arch.sev_info;
+
+ __sev_asid_free(sev->asid);
+}
+
+static void sev_vm_destroy(struct kvm *kvm)
+{
+ if (!sev_guest(kvm))
+ return;
+
+ sev_asid_free(kvm);
+}
+
static void avic_vm_destroy(struct kvm *kvm)
{
unsigned long flags;
@@ -1484,6 +1537,12 @@ 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;
@@ -5556,6 +5615,75 @@ static int enable_smi_window(struct kvm_vcpu *vcpu)
return 0;
}

+static int sev_asid_new(void)
+{
+ int pos;
+
+ /*
+ * SEV-enabled guest must use asid from min_sev_asid to max_sev_asid.
+ */
+ pos = find_next_zero_bit(sev_asid_bitmap, max_sev_asid, min_sev_asid - 1);
+ if (pos >= max_sev_asid)
+ return -EBUSY;
+
+ set_bit(pos, sev_asid_bitmap);
+ return pos + 1;
+}
+
+static int sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp)
+{
+ struct kvm_sev_info *sev = &kvm->arch.sev_info;
+ int asid, ret;
+
+ ret = -EBUSY;
+ asid = sev_asid_new();
+ if (asid < 0)
+ return ret;
+
+ ret = sev_platform_init(&argp->error);
+ if (ret)
+ goto e_free;
+
+ sev->active = true;
+ sev->asid = asid;
+
+ return 0;
+
+e_free:
+ __sev_asid_free(asid);
+ return ret;
+}
+
+static int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
+{
+ struct kvm_sev_cmd sev_cmd;
+ int r;
+
+ if (!svm_sev_enabled())
+ return -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:
+ r = -EINVAL;
+ goto out;
+ }
+
+ if (copy_to_user(argp, &sev_cmd, sizeof(struct kvm_sev_cmd)))
+ r = -EFAULT;
+
+out:
+ mutex_unlock(&kvm->lock);
+ return r;
+}
+
static struct kvm_x86_ops svm_x86_ops __ro_after_init = {
.cpu_has_kvm_support = has_svm,
.disabled_by_bios = is_disabled,
@@ -5572,7 +5700,7 @@ 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,
@@ -5671,6 +5799,8 @@ static struct kvm_x86_ops svm_x86_ops __ro_after_init = {
.pre_enter_smm = svm_pre_enter_smm,
.pre_leave_smm = svm_pre_leave_smm,
.enable_smi_window = enable_smi_window,
+
+ .mem_enc_op = svm_mem_enc_op,
};

static int __init svm_init(void)
--
2.9.5
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