The patch adds initial support required for Secure Encrypted
Virtualization (SEV) guest management API's.
ASID management:
- Reserve asid range for SEV guest, SEV asid range is obtained
through CPUID Fn8000_001f[ECX]. A non-SEV guest can use any
asid outside the SEV asid range.
- SEV guest must have asid value within asid range obtained
through CPUID.
- SEV guest must have the same asid for all vcpu's. A TLB flush
is required if different vcpu for the same ASID is to be run
on the same host CPU.
- save SEV private structure in kvm_arch.
- If SEV is available then initialize PSP firmware during hardware probe
Signed-off-by: Brijesh Singh <brijesh.singh@xxxxxxx>
---
arch/x86/include/asm/kvm_host.h | 9 ++
arch/x86/kvm/svm.c | 213 +++++++++++++++++++++++++++++++++++++++
2 files changed, 221 insertions(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index b1dd673..9b885fc 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -715,6 +715,12 @@ struct kvm_hv {
u64 hv_crash_ctl;
};
+struct kvm_sev_info {
+ unsigned int asid; /* asid for this guest */
+ unsigned int handle; /* firmware handle */
+ unsigned int ref_count; /* number of active vcpus */
+};
+
struct kvm_arch {
unsigned int n_used_mmu_pages;
unsigned int n_requested_mmu_pages;
@@ -799,6 +805,9 @@ struct kvm_arch {
bool x2apic_format;
bool x2apic_broadcast_quirk_disabled;
+
+ /* struct for SEV guest */
+ 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 f010b23..dcee635 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -34,6 +34,7 @@
#include <linux/sched.h>
#include <linux/trace_events.h>
#include <linux/slab.h>
+#include <linux/ccp-psp.h>
#include <asm/apic.h>
#include <asm/perf_event.h>
@@ -186,6 +187,9 @@ struct vcpu_svm {
struct page *avic_backing_page;
u64 *avic_physical_id_cache;
bool avic_is_running;
+
+ /* which host cpu was used for running this vcpu */
+ bool last_cpuid;
};
#define AVIC_LOGICAL_ID_ENTRY_GUEST_PHYSICAL_ID_MASK (0xFF)
@@ -243,6 +247,25 @@ static int avic;
module_param(avic, int, S_IRUGO);
#endif
+/* Secure Encrypted Virtualization */
+static bool sev_enabled;
+static unsigned long max_sev_asid;
+static unsigned long *sev_asid_bitmap;
+
+#define kvm_sev_guest() (kvm->arch.sev_info.handle)
+#define kvm_sev_handle() (kvm->arch.sev_info.handle)
+#define kvm_sev_ref() (kvm->arch.sev_info.ref_count++)
+#define kvm_sev_unref() (kvm->arch.sev_info.ref_count--)
+#define svm_sev_handle() (svm->vcpu.kvm->arch.sev_info.handle)
+#define svm_sev_asid() (svm->vcpu.kvm->arch.sev_info.asid)
+#define svm_sev_ref() (svm->vcpu.kvm->arch.sev_info.ref_count++)
+#define svm_sev_unref() (svm->vcpu.kvm->arch.sev_info.ref_count--)
+#define svm_sev_guest() (svm->vcpu.kvm->arch.sev_info.handle)
+#define svm_sev_ref_count() (svm->vcpu.kvm->arch.sev_info.ref_count)
+
+static int sev_asid_new(void);
+static void sev_asid_free(int asid);
+
static void svm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0);
static void svm_flush_tlb(struct kvm_vcpu *vcpu);
static void svm_complete_interrupts(struct vcpu_svm *svm);
@@ -474,6 +497,8 @@ struct svm_cpu_data {
struct kvm_ldttss_desc *tss_desc;
struct page *save_area;
+
+ void **sev_vmcb; /* index = sev_asid, value = vmcb pointer */
};
static DEFINE_PER_CPU(struct svm_cpu_data *, svm_data);
@@ -727,7 +752,10 @@ static int svm_hardware_enable(void)
sd->asid_generation = 1;
sd->max_asid = cpuid_ebx(SVM_CPUID_FUNC) - 1;
sd->next_asid = sd->max_asid + 1;
- sd->min_asid = 1;
+ sd->min_asid = max_sev_asid + 1;
+
+ if (sev_enabled)
+ memset(sd->sev_vmcb, 0, (max_sev_asid + 1) * sizeof(void *));
native_store_gdt(&gdt_descr);
gdt = (struct desc_struct *)gdt_descr.address;
@@ -788,6 +816,7 @@ static void svm_cpu_uninit(int cpu)
per_cpu(svm_data, raw_smp_processor_id()) = NULL;
__free_page(sd->save_area);
+ kfree(sd->sev_vmcb);
kfree(sd);
}
@@ -805,6 +834,14 @@ static int svm_cpu_init(int cpu)
if (!sd->save_area)
goto err_1;
+ if (sev_enabled) {
+ sd->sev_vmcb = kmalloc((max_sev_asid + 1) * sizeof(void *),
+ GFP_KERNEL);
+ r = -ENOMEM;
+ if (!sd->sev_vmcb)
+ goto err_1;
+ }
+
per_cpu(svm_data, cpu) = sd;
return 0;
@@ -931,6 +968,74 @@ static void svm_disable_lbrv(struct vcpu_svm *svm)
set_msr_interception(msrpm, MSR_IA32_LASTINTTOIP, 0, 0);
}
+static __init void sev_hardware_setup(void)
+{
+ int ret, psp_ret;
+ struct psp_data_init *init;
+ struct psp_data_status *status;
+
+ /*
+ * Check SEV Feature Support: Fn8001_001F[EAX]
+ * Bit 1: Secure Memory Virtualization supported
+ */
+ if (!(cpuid_eax(0x8000001F) & 0x2))
+ return;
+
+ /*
+ * Get maximum number of encrypted guest supported: Fn8001_001F[ECX]
+ * Bit 31:0: Number of supported guest
+ */
+ max_sev_asid = cpuid_ecx(0x8000001F);
+ if (!max_sev_asid)
+ return;
+
+ init = kzalloc(sizeof(*init), GFP_KERNEL);
+ if (!init)
+ return;
+
+ status = kzalloc(sizeof(*status), GFP_KERNEL);
+ if (!status)
+ goto err_1;
+
+ /* Initialize PSP firmware */
+ init->hdr.buffer_len = sizeof(*init);
+ init->flags = 0;
+ ret = psp_platform_init(init, &psp_ret);
+ if (ret) {
+ printk(KERN_ERR "SEV: PSP_INIT ret=%d (%#x)\n", ret, psp_ret);
+ goto err_2;
+ }
+
+ /* Initialize SEV ASID bitmap */
+ sev_asid_bitmap = kmalloc(max(sizeof(unsigned long),
+ max_sev_asid/8 + 1), GFP_KERNEL);
+ if (IS_ERR(sev_asid_bitmap)) {
+ psp_platform_shutdown(&psp_ret);
+ goto err_2;
+ }
+ bitmap_zero(sev_asid_bitmap, max_sev_asid);
+ set_bit(0, sev_asid_bitmap); /* mark ASID 0 as used */
+
+ sev_enabled = 1;
+ printk(KERN_INFO "kvm: SEV enabled\n");
+
+ /* Query the platform status and print API version */
+ status->hdr.buffer_len = sizeof(*status);
+ ret = psp_platform_status(status, &psp_ret);
+ if (ret) {
+ printk(KERN_ERR "SEV: PLATFORM_STATUS ret=%#x\n", psp_ret);
+ goto err_2;
+ }
+
+ printk(KERN_INFO "SEV API: %d.%d\n",
+ status->api_major, status->api_minor);
+err_2:
+ kfree(status);
+err_1:
+ kfree(init);
+ return;
+}
+
static __init int svm_hardware_setup(void)
{
int cpu;
@@ -966,6 +1071,8 @@ static __init int svm_hardware_setup(void)
kvm_enable_efer_bits(EFER_SVME | EFER_LMSLE);
}
+ sev_hardware_setup();
+
for_each_possible_cpu(cpu) {
r = svm_cpu_init(cpu);
if (r)
@@ -1003,10 +1110,25 @@ err:
return r;
}
+static __exit void sev_hardware_unsetup(void)
+{
+ int ret, psp_ret;
+
+ ret = psp_platform_shutdown(&psp_ret);
+ if (ret)
+ printk(KERN_ERR "failed to shutdown PSP rc=%d (%#0x10x)\n",
+ ret, psp_ret);
+
+ kfree(sev_asid_bitmap);
+}
+
static __exit void svm_hardware_unsetup(void)
{
int cpu;
+ if (sev_enabled)
+ sev_hardware_unsetup();
+
for_each_possible_cpu(cpu)
svm_cpu_uninit(cpu);
@@ -1088,6 +1210,11 @@ static void avic_init_vmcb(struct vcpu_svm *svm)
svm->vcpu.arch.apicv_active = true;
}
+static void sev_init_vmcb(struct vcpu_svm *svm)
+{
+ svm->vmcb->control.nested_ctl |= SVM_NESTED_CTL_SEV_ENABLE;
+}
+
static void init_vmcb(struct vcpu_svm *svm)
{
struct vmcb_control_area *control = &svm->vmcb->control;
@@ -1202,6 +1329,10 @@ static void init_vmcb(struct vcpu_svm *svm)
if (avic)
avic_init_vmcb(svm);
+ if (svm_sev_guest())
+ sev_init_vmcb(svm);
+
+
mark_all_dirty(svm->vmcb);
enable_gif(svm);
@@ -1413,6 +1544,14 @@ static void svm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
avic_update_vapic_bar(svm, APIC_DEFAULT_PHYS_BASE);
}
+static void sev_init_vcpu(struct vcpu_svm *svm)
+{
+ if (!svm_sev_guest())
+ return;
+
+ svm_sev_ref();
+}
+
static struct kvm_vcpu *svm_create_vcpu(struct kvm *kvm, unsigned int id)
{
struct vcpu_svm *svm;
@@ -1475,6 +1614,7 @@ static struct kvm_vcpu *svm_create_vcpu(struct kvm *kvm, unsigned int id)
init_vmcb(svm);
svm_init_osvw(&svm->vcpu);
+ sev_init_vcpu(svm);
return &svm->vcpu;
@@ -1494,6 +1634,23 @@ out:
return ERR_PTR(err);
}
+static void sev_uninit_vcpu(struct vcpu_svm *svm)
+{
+ int cpu;
+ int asid = svm_sev_asid();
+ struct svm_cpu_data *sd;
+
+ if (!svm_sev_guest())
+ return;
+
+ svm_sev_unref();
+
+ for_each_possible_cpu(cpu) {
+ sd = per_cpu(svm_data, cpu);
+ sd->sev_vmcb[asid] = NULL;
+ }
+}
+
static void svm_free_vcpu(struct kvm_vcpu *vcpu)
{
struct vcpu_svm *svm = to_svm(vcpu);
@@ -1502,6 +1659,7 @@ static void svm_free_vcpu(struct kvm_vcpu *vcpu)
__free_pages(virt_to_page(svm->msrpm), MSRPM_ALLOC_ORDER);
__free_page(virt_to_page(svm->nested.hsave));
__free_pages(virt_to_page(svm->nested.msrpm), MSRPM_ALLOC_ORDER);
+ sev_uninit_vcpu(svm);
kvm_vcpu_uninit(vcpu);
kmem_cache_free(kvm_vcpu_cache, svm);
}
@@ -1945,6 +2103,11 @@ static int pf_interception(struct vcpu_svm *svm)
default:
error_code = svm->vmcb->control.exit_info_1;
+ /* In SEV mode, the guest physical address will have C-bit
+ * set. C-bit must be cleared before handling the fault.
+ */
+ if (svm_sev_guest())
+ fault_address &= ~sme_me_mask;
trace_kvm_page_fault(fault_address, error_code);
if (!npt_enabled && kvm_event_needs_reinjection(&svm->vcpu))
kvm_mmu_unprotect_page_virt(&svm->vcpu, fault_address);
@@ -4131,12 +4294,40 @@ static void reload_tss(struct kvm_vcpu *vcpu)
load_TR_desc();
}
+static void pre_sev_run(struct vcpu_svm *svm)
+{
+ int asid = svm_sev_asid();
+ int cpu = raw_smp_processor_id();
+ struct svm_cpu_data *sd = per_cpu(svm_data, cpu);
+
+ /* Assign the asid allocated for this SEV guest */
+ svm->vmcb->control.asid = svm_sev_asid();
+
+ /* Flush guest TLB:
+ * - when different VMCB for the same ASID is to be run on the
+ * same host CPU
+ * or
+ * - this VMCB was executed on different host cpu in previous VMRUNs.
+ */
+ if (sd->sev_vmcb[asid] != (void *)svm->vmcb ||
+ svm->last_cpuid != cpu)
+ svm->vmcb->control.tlb_ctl = TLB_CONTROL_FLUSH_ALL_ASID;
+
+ svm->last_cpuid = cpu;
+ sd->sev_vmcb[asid] = (void *)svm->vmcb;
+
+ mark_dirty(svm->vmcb, VMCB_ASID);
+}
+
static void pre_svm_run(struct vcpu_svm *svm)
{
int cpu = raw_smp_processor_id();
struct svm_cpu_data *sd = per_cpu(svm_data, cpu);
+ if (svm_sev_guest())
+ return pre_sev_run(svm);
+
/* FIXME: handle wraparound of asid_generation */
if (svm->asid_generation != sd->asid_generation)
new_asid(svm, sd);
@@ -4985,6 +5176,26 @@ 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 (!sev_enabled)
+ return -ENOTTY;
+
+ 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;
+}
+
+static void sev_asid_free(int asid)
+{
+ clear_bit(asid, sev_asid_bitmap);
+}
+
static struct kvm_x86_ops svm_x86_ops __ro_after_init = {
.cpu_has_kvm_support = has_svm,
.disabled_by_bios = is_disabled,
--
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