This hypercall is used by the SEV guest to notify a change in the page
encryption status to the hypervisor. The hypercall should be invoked
only when the encryption attribute is changed from encrypted -> decrypted
and vice versa. By default all guest pages are considered encrypted.
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: "Radim Krčmář" <rkrcmar@xxxxxxxxxx>
Cc: Joerg Roedel <joro@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxx>
Cc: Tom Lendacky <thomas.lendacky@xxxxxxx>
Cc: x86@xxxxxxxxxx
Cc: kvm@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Brijesh Singh <brijesh.singh@xxxxxxx>
---
Documentation/virtual/kvm/hypercalls.txt | 14 +++++
arch/x86/include/asm/kvm_host.h | 2 +
arch/x86/kvm/svm.c | 70 ++++++++++++++++++++++++
arch/x86/kvm/vmx/vmx.c | 1 +
arch/x86/kvm/x86.c | 5 ++
include/uapi/linux/kvm_para.h | 1 +
6 files changed, 93 insertions(+)
diff --git a/Documentation/virtual/kvm/hypercalls.txt b/Documentation/virtual/kvm/hypercalls.txt
index da24c138c8d1..94f0611f4d88 100644
--- a/Documentation/virtual/kvm/hypercalls.txt
+++ b/Documentation/virtual/kvm/hypercalls.txt
@@ -141,3 +141,17 @@ a0 corresponds to the APIC ID in the third argument (a2), bit 1
corresponds to the APIC ID a2+1, and so on.
Returns the number of CPUs to which the IPIs were delivered successfully.
+
+7. KVM_HC_PAGE_ENC_STATUS
+-------------------------
+Architecture: x86
+Status: active
+Purpose: Notify the encryption status changes in guest page table (SEV guest)
+
+a0: the guest physical address of the start page
+a1: the number of pages
+a2: encryption attribute
+
+ Where:
+ * 1: Encryption attribute is set
+ * 0: Encryption attribute is cleared
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 26d1eb83f72a..b463a81dc176 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1199,6 +1199,8 @@ struct kvm_x86_ops {
uint16_t (*nested_get_evmcs_version)(struct kvm_vcpu *vcpu);
bool (*need_emulation_on_page_fault)(struct kvm_vcpu *vcpu);
+ int (*page_enc_status_hc)(struct kvm *kvm, unsigned long gpa,
+ unsigned long sz, unsigned long mode);
};
struct kvm_arch_async_pf {
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 3089942f6630..431718309359 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -135,6 +135,8 @@ struct kvm_sev_info {
int fd; /* SEV device fd */
unsigned long pages_locked; /* Number of pages locked */
struct list_head regions_list; /* List of registered regions */
+ unsigned long *page_enc_bmap;
+ unsigned long page_enc_bmap_size;
};
struct kvm_svm {
@@ -1910,6 +1912,8 @@ static void sev_vm_destroy(struct kvm *kvm)
sev_unbind_asid(kvm, sev->handle);
sev_asid_free(kvm);
+
+ kvfree(sev->page_enc_bmap);
}
static void avic_vm_destroy(struct kvm *kvm)
@@ -2084,6 +2088,7 @@ static void avic_set_running(struct kvm_vcpu *vcpu, bool is_run)
static void svm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
{
+ struct kvm_sev_info *sev = &to_kvm_svm(vcpu->kvm)->sev_info;
struct vcpu_svm *svm = to_svm(vcpu);
u32 dummy;
u32 eax = 1;
@@ -2105,6 +2110,12 @@ static void svm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
if (kvm_vcpu_apicv_active(vcpu) && !init_event)
avic_update_vapic_bar(svm, APIC_DEFAULT_PHYS_BASE);
+
+ /* reset the page encryption bitmap */
+ if (sev_guest(vcpu->kvm)) {
+ kvfree(sev->page_enc_bmap);
+ sev->page_enc_bmap_size = 0;
+ }
}
static int avic_init_vcpu(struct vcpu_svm *svm)
@@ -7357,6 +7368,63 @@ static int sev_receive_finish(struct kvm *kvm, struct kvm_sev_cmd *argp)
return ret;
}
+static int sev_resize_page_enc_bitmap(struct kvm *kvm, unsigned long new_size)
+{
+ struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
+ unsigned long *map;
+ unsigned long sz;
+
+ if (sev->page_enc_bmap_size >= new_size)
+ return 0;
+
+ sz = ALIGN(new_size, BITS_PER_LONG) / 8;
+
+ map = vmalloc(sz);
+ if (!map) {
+ pr_err_once("Failed to allocate decrypted bitmap size %lx\n", sz);
+ return -ENOMEM;
+ }
+
+ /* mark the page encrypted (by default) */
+ memset(map, 0xff, sz);
+
+ bitmap_copy(map, sev->page_enc_bmap, sev->page_enc_bmap_size);
+ kvfree(sev->page_enc_bmap);
+
+ sev->page_enc_bmap = map;
+ sev->page_enc_bmap_size = new_size;
+
+ return 0;
+}
+
+static int svm_page_enc_status_hc(struct kvm *kvm, unsigned long gpa,
+ unsigned long npages, unsigned long enc)
+{
+ struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
+ gfn_t gfn_start, gfn_end;
+ int ret;
+
+ if (!npages)
+ return 0;
+
+ gfn_start = gpa_to_gfn(gpa);
+ gfn_end = gfn_start + npages;
+
+ mutex_lock(&kvm->lock);
+ ret = sev_resize_page_enc_bitmap(kvm, gfn_end);
+ if (ret)
+ goto unlock;
+
+ if (enc)
+ __bitmap_set(sev->page_enc_bmap, gfn_start, gfn_end - gfn_start);
+ else
+ __bitmap_clear(sev->page_enc_bmap, gfn_start, gfn_end - gfn_start);
+
+unlock:
+ mutex_unlock(&kvm->lock);
+ return ret;
+}
+
static int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
{
struct kvm_sev_cmd sev_cmd;
@@ -7698,6 +7766,8 @@ static struct kvm_x86_ops svm_x86_ops __ro_after_init = {
.nested_get_evmcs_version = nested_get_evmcs_version,
.need_emulation_on_page_fault = svm_need_emulation_on_page_fault,
+
+ .page_enc_status_hc = svm_page_enc_status_hc
};
static int __init svm_init(void)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index d98eac371c0a..78f8a93fc6dd 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -7724,6 +7724,7 @@ static struct kvm_x86_ops vmx_x86_ops __ro_after_init = {
.get_vmcs12_pages = NULL,
.nested_enable_evmcs = NULL,
.need_emulation_on_page_fault = vmx_need_emulation_on_page_fault,
+ .page_enc_status_hc = NULL,
};
static void vmx_cleanup_l1d_flush(void)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 63bb1ee8258e..6baf48ec0ed4 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -7219,6 +7219,11 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
case KVM_HC_SEND_IPI:
ret = kvm_pv_send_ipi(vcpu->kvm, a0, a1, a2, a3, op_64_bit);
break;
+ case KVM_HC_PAGE_ENC_STATUS:
+ ret = -KVM_ENOSYS;
+ if (kvm_x86_ops->page_enc_status_hc)
+ ret = kvm_x86_ops->page_enc_status_hc(vcpu->kvm, a0, a1, a2);
+ break;
default:
ret = -KVM_ENOSYS;
break;
diff --git a/include/uapi/linux/kvm_para.h b/include/uapi/linux/kvm_para.h
index 6c0ce49931e5..3dc9e579f4f9 100644
--- a/include/uapi/linux/kvm_para.h
+++ b/include/uapi/linux/kvm_para.h
@@ -28,6 +28,7 @@
#define KVM_HC_MIPS_CONSOLE_OUTPUT 8
#define KVM_HC_CLOCK_PAIRING 9
#define KVM_HC_SEND_IPI 10
+#define KVM_HC_PAGE_ENC_STATUS 11
/*
* hypercalls use architecture specific
--
2.17.1
