The ioctl can be used to set page encryption bitmap for an
incoming guest.
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Paolo Bonzini <[email protected]>
Cc: "Radim Krčmář" <[email protected]>
Cc: Joerg Roedel <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Tom Lendacky <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Brijesh Singh <[email protected]>
---
Documentation/virtual/kvm/api.txt | 21 +++++++++++++++
arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/kvm/svm.c | 44 ++++++++++++++++++++++++++++++-
arch/x86/kvm/x86.c | 12 +++++++++
include/uapi/linux/kvm.h | 1 +
5 files changed, 78 insertions(+), 1 deletion(-)
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index ed61a4d63b10..1073004f178e 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -4107,6 +4107,27 @@ or shared. The bitmap can be used during the guest migration, if the page
is private then userspace need to use SEV migration commands to transmit
the page.
+4.121 KVM_SET_PAGE_ENC_BITMAP (vm ioctl)
+
+Capability: basic
+Architectures: x86
+Type: vm ioctl
+Parameters: struct kvm_page_enc_bitmap (in/out)
+Returns: 0 on success, -1 on error
+
+/* for KVM_SET_PAGE_ENC_BITMAP */
+struct kvm_page_enc_bitmap {
+ __u64 start_gfn;
+ __u64 num_pages;
+ union {
+ void __user *enc_bitmap; /* one bit per page */
+ __u64 padding2;
+ };
+};
+
+During the guest live migration the outgoing guest exports its page encryption
+bitmap, the KVM_SET_PAGE_ENC_BITMAP can be used to build the page encryption
+bitmap for an incoming guest.
5. The kvm_run structure
------------------------
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 9df0e2315543..369a06b275d5 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1202,6 +1202,7 @@ struct kvm_x86_ops {
int (*page_enc_status_hc)(struct kvm *kvm, unsigned long gpa,
unsigned long sz, unsigned long mode);
int (*get_page_enc_bitmap)(struct kvm *kvm, struct kvm_page_enc_bitmap *bmap);
+ int (*set_page_enc_bitmap)(struct kvm *kvm, struct kvm_page_enc_bitmap *bmap);
};
struct kvm_arch_async_pf {
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index e675fd89bb9a..31653e8d5927 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -7466,6 +7466,47 @@ static int svm_get_page_enc_bitmap(struct kvm *kvm,
return ret;
}
+static int svm_set_page_enc_bitmap(struct kvm *kvm,
+ struct kvm_page_enc_bitmap *bmap)
+{
+ struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
+ unsigned long gfn_start, gfn_end;
+ unsigned long *bitmap;
+ unsigned long sz, i;
+ int ret;
+
+ if (!sev_guest(kvm))
+ return -ENOTTY;
+
+ gfn_start = bmap->start_gfn;
+ gfn_end = gfn_start + bmap->num_pages;
+
+ sz = ALIGN(bmap->num_pages, BITS_PER_LONG) / 8;
+ bitmap = kmalloc(sz, GFP_KERNEL);
+ if (!bitmap)
+ return -ENOMEM;
+
+ ret = -EFAULT;
+ if (copy_from_user(bitmap, bmap->enc_bitmap, sz))
+ goto out;
+
+ mutex_lock(&kvm->lock);
+ ret = sev_resize_page_enc_bitmap(kvm, gfn_end);
+ if (ret)
+ goto unlock;
+
+ i = gfn_start;
+ for_each_clear_bit_from(i, bitmap, (gfn_end - gfn_start))
+ clear_bit(i + gfn_start, sev->page_enc_bmap);
+
+ ret = 0;
+unlock:
+ mutex_unlock(&kvm->lock);
+out:
+ kfree(bitmap);
+ return ret;
+}
+
static int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
{
struct kvm_sev_cmd sev_cmd;
@@ -7809,7 +7850,8 @@ static struct kvm_x86_ops svm_x86_ops __ro_after_init = {
.need_emulation_on_page_fault = svm_need_emulation_on_page_fault,
.page_enc_status_hc = svm_page_enc_status_hc,
- .get_page_enc_bitmap = svm_get_page_enc_bitmap
+ .get_page_enc_bitmap = svm_get_page_enc_bitmap,
+ .set_page_enc_bitmap = svm_set_page_enc_bitmap
};
static int __init svm_init(void)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 59ae49b1b914..ea21cb1cbfb7 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4939,6 +4939,18 @@ long kvm_arch_vm_ioctl(struct file *filp,
r = kvm_x86_ops->get_page_enc_bitmap(kvm, &bitmap);
break;
}
+ case KVM_SET_PAGE_ENC_BITMAP: {
+ struct kvm_page_enc_bitmap bitmap;
+
+ r = -EFAULT;
+ if (copy_from_user(&bitmap, argp, sizeof(bitmap)))
+ goto out;
+
+ r = -ENOTTY;
+ if (kvm_x86_ops->set_page_enc_bitmap)
+ r = kvm_x86_ops->set_page_enc_bitmap(kvm, &bitmap);
+ break;
+ }
default:
r = -ENOTTY;
}
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 0d08bcf94ef5..90dd336e8080 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -1462,6 +1462,7 @@ struct kvm_enc_region {
#define KVM_ARM_VCPU_FINALIZE _IOW(KVMIO, 0xc2, int)
#define KVM_GET_PAGE_ENC_BITMAP _IOW(KVMIO, 0xc2, struct kvm_page_enc_bitmap)
+#define KVM_SET_PAGE_ENC_BITMAP _IOW(KVMIO, 0xc3, struct kvm_page_enc_bitmap)
/* Secure Encrypted Virtualization command */
enum sev_cmd_id {
--
2.17.1
On Wed, Jul 10, 2019 at 1:13 PM Singh, Brijesh <[email protected]> wrote:
>
> struct kvm_arch_async_pf {
> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
> index e675fd89bb9a..31653e8d5927 100644
> --- a/arch/x86/kvm/svm.c
> +++ b/arch/x86/kvm/svm.c
> @@ -7466,6 +7466,47 @@ static int svm_get_page_enc_bitmap(struct kvm *kvm,
> return ret;
> }
>
> +static int svm_set_page_enc_bitmap(struct kvm *kvm,
> + struct kvm_page_enc_bitmap *bmap)
> +{
> + struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
> + unsigned long gfn_start, gfn_end;
> + unsigned long *bitmap;
> + unsigned long sz, i;
> + int ret;
> +
> + if (!sev_guest(kvm))
> + return -ENOTTY;
> +
> + gfn_start = bmap->start_gfn;
> + gfn_end = gfn_start + bmap->num_pages;
> +
> + sz = ALIGN(bmap->num_pages, BITS_PER_LONG) / 8;
> + bitmap = kmalloc(sz, GFP_KERNEL);
This kmalloc should probably be either a vmalloc or kvmalloc. The max
size, if I'm reading kmalloc correctly, is 2^10 pages. That's 4MB,
which should correspond to a bitmap for a 128GB VM, which is a
plausible VM size.
--Steve
On Thu, Nov 14, 2019 at 5:22 PM Steve Rutherford <[email protected]> wrote:
>
> On Wed, Jul 10, 2019 at 1:13 PM Singh, Brijesh <[email protected]> wrote:
> >
> > struct kvm_arch_async_pf {
> > diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
> > index e675fd89bb9a..31653e8d5927 100644
> > --- a/arch/x86/kvm/svm.c
> > +++ b/arch/x86/kvm/svm.c
> > @@ -7466,6 +7466,47 @@ static int svm_get_page_enc_bitmap(struct kvm *kvm,
> > return ret;
> > }
> >
> > +static int svm_set_page_enc_bitmap(struct kvm *kvm,
> > + struct kvm_page_enc_bitmap *bmap)
> > +{
> > + struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
> > + unsigned long gfn_start, gfn_end;
> > + unsigned long *bitmap;
> > + unsigned long sz, i;
> > + int ret;
> > +
> > + if (!sev_guest(kvm))
> > + return -ENOTTY;
> > +
> > + gfn_start = bmap->start_gfn;
> > + gfn_end = gfn_start + bmap->num_pages;
> > +
> > + sz = ALIGN(bmap->num_pages, BITS_PER_LONG) / 8;
> > + bitmap = kmalloc(sz, GFP_KERNEL);
>
> This kmalloc should probably be either a vmalloc or kvmalloc. The max
> size, if I'm reading kmalloc correctly, is 2^10 pages. That's 4MB,
> which should correspond to a bitmap for a 128GB VM, which is a
> plausible VM size.
>
> --Steve
Ignore this, you are clearly never going to copy that much in one
call, and the backing bitmap correctly uses kvmalloc.