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Date: Thu, 20 Jun 2019 16:38:56 +0000
From: "Singh, Brijesh" <brijesh.singh@....com>
To: "kvm@...r.kernel.org" <kvm@...r.kernel.org>
CC: "Singh, Brijesh" <brijesh.singh@....com>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>,
"H. Peter Anvin" <hpa@...or.com>,
Paolo Bonzini <pbonzini@...hat.com>,
Radim Krčmář <rkrcmar@...hat.com>,
Joerg Roedel <joro@...tes.org>, Borislav Petkov <bp@...e.de>,
"Lendacky, Thomas" <Thomas.Lendacky@....com>,
"x86@...nel.org" <x86@...nel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: [RFC PATCH v2 08/11] KVM: X86: Introduce KVM_HC_PAGE_ENC_STATUS
hypercall
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@...utronix.de>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: "H. Peter Anvin" <hpa@...or.com>
Cc: Paolo Bonzini <pbonzini@...hat.com>
Cc: "Radim Krčmář" <rkrcmar@...hat.com>
Cc: Joerg Roedel <joro@...tes.org>
Cc: Borislav Petkov <bp@...e.de>
Cc: Tom Lendacky <thomas.lendacky@....com>
Cc: x86@...nel.org
Cc: kvm@...r.kernel.org
Cc: linux-kernel@...r.kernel.org
Signed-off-by: Brijesh Singh <brijesh.singh@....com>
---
Documentation/virtual/kvm/hypercalls.txt | 14 ++++++
arch/x86/include/asm/kvm_host.h | 2 +
arch/x86/kvm/svm.c | 63 ++++++++++++++++++++++++
arch/x86/kvm/vmx/vmx.c | 1 +
arch/x86/kvm/x86.c | 5 ++
include/uapi/linux/kvm_para.h | 1 +
6 files changed, 86 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 450d69a1e6fa..a54fef979a8e 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1202,6 +1202,8 @@ 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 90e32e3f2a8b..b47a05a5e137 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -138,6 +138,8 @@ 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 {
@@ -1913,6 +1915,8 @@ 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)
@@ -7360,6 +7364,63 @@ 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;
@@ -7701,6 +7762,8 @@ 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 b93e36ddee5e..b0fc6c322a75 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -7727,6 +7727,7 @@ 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 83aefd759846..88a672da68d5 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -7221,6 +7221,11 @@ 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
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