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KVM: SVM: Add KVM_SEND_UPDATE_DATA command 

The command is used for encrypting the guest memory region using the encryption
context created with KVM_SEV_SEND_START.

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: 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
Reviewed-by : Steve Rutherford <srutherford@google.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
Message-Id: <d6a6ea740b0c668b30905ae31eac5ad7da048bb3.1618498113.git.ashish.kalra@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Brijesh Singh 2021-04-15 15:53:55 +00:00 committed by Paolo Bonzini
parent 4cfdd47d6d
commit d3d1af85e2
3 changed files with 162 additions and 0 deletions
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28
Documentation/virt/kvm/amd-memory-encryption.rst
View File

@ -320,6 +320,34 @@ Returns: 0 on success, -negative on error
__u32 session_len;
};
12. KVM_SEV_SEND_UPDATE_DATA
----------------------------
The KVM_SEV_SEND_UPDATE_DATA command can be used by the hypervisor to encrypt the
outgoing guest memory region with the encryption context creating using
KVM_SEV_SEND_START.
If hdr_len or trans_len are zero on entry, the length of the packet header and
transport region are written to hdr_len and trans_len respectively, and all
other fields are not used.
Parameters (in): struct kvm_sev_send_update_data
Returns: 0 on success, -negative on error
::
struct kvm_sev_launch_send_update_data {
__u64 hdr_uaddr; /* userspace address containing the packet header */
__u32 hdr_len;
__u64 guest_uaddr; /* the source memory region to be encrypted */
__u32 guest_len;
__u64 trans_uaddr; /* the destination memory region */
__u32 trans_len;
};
References
==========

125
arch/x86/kvm/svm/sev.c
View File

@ -34,6 +34,7 @@ static DECLARE_RWSEM(sev_deactivate_lock);
static DEFINE_MUTEX(sev_bitmap_lock);
unsigned int max_sev_asid;
static unsigned int min_sev_asid;
static unsigned long sev_me_mask;
static unsigned long *sev_asid_bitmap;
static unsigned long *sev_reclaim_asid_bitmap;
@ -1236,6 +1237,126 @@ static int sev_send_start(struct kvm *kvm, struct kvm_sev_cmd *argp)
return ret;
}
/* Userspace wants to query either header or trans length. */
static int
__sev_send_update_data_query_lengths(struct kvm *kvm, struct kvm_sev_cmd *argp,
struct kvm_sev_send_update_data *params)
{
struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
struct sev_data_send_update_data *data;
int ret;
data = kzalloc(sizeof(*data), GFP_KERNEL_ACCOUNT);
if (!data)
return -ENOMEM;
data->handle = sev->handle;
ret = sev_issue_cmd(kvm, SEV_CMD_SEND_UPDATE_DATA, data, &argp->error);
if (ret < 0)
goto out;
params->hdr_len = data->hdr_len;
params->trans_len = data->trans_len;
if (copy_to_user((void __user *)(uintptr_t)argp->data, params,
sizeof(struct kvm_sev_send_update_data)))
ret = -EFAULT;
out:
kfree(data);
return ret;
}
static int sev_send_update_data(struct kvm *kvm, struct kvm_sev_cmd *argp)
{
struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
struct sev_data_send_update_data *data;
struct kvm_sev_send_update_data params;
void *hdr, *trans_data;
struct page **guest_page;
unsigned long n;
int ret, offset;
if (!sev_guest(kvm))
return -ENOTTY;
if (copy_from_user(&params, (void __user *)(uintptr_t)argp->data,
sizeof(struct kvm_sev_send_update_data)))
return -EFAULT;
/* userspace wants to query either header or trans length */
if (!params.trans_len || !params.hdr_len)
return __sev_send_update_data_query_lengths(kvm, argp, &params);
if (!params.trans_uaddr || !params.guest_uaddr ||
!params.guest_len || !params.hdr_uaddr)
return -EINVAL;
/* Check if we are crossing the page boundary */
offset = params.guest_uaddr & (PAGE_SIZE - 1);
if ((params.guest_len + offset > PAGE_SIZE))
return -EINVAL;
/* Pin guest memory */
guest_page = sev_pin_memory(kvm, params.guest_uaddr & PAGE_MASK,
PAGE_SIZE, &n, 0);
if (!guest_page)
return -EFAULT;
/* allocate memory for header and transport buffer */
ret = -ENOMEM;
hdr = kmalloc(params.hdr_len, GFP_KERNEL_ACCOUNT);
if (!hdr)
goto e_unpin;
trans_data = kmalloc(params.trans_len, GFP_KERNEL_ACCOUNT);
if (!trans_data)
goto e_free_hdr;
data = kzalloc(sizeof(*data), GFP_KERNEL);
if (!data)
goto e_free_trans_data;
data->hdr_address = __psp_pa(hdr);
data->hdr_len = params.hdr_len;
data->trans_address = __psp_pa(trans_data);
data->trans_len = params.trans_len;
/* The SEND_UPDATE_DATA command requires C-bit to be always set. */
data->guest_address = (page_to_pfn(guest_page[0]) << PAGE_SHIFT) +
offset;
data->guest_address |= sev_me_mask;
data->guest_len = params.guest_len;
data->handle = sev->handle;
ret = sev_issue_cmd(kvm, SEV_CMD_SEND_UPDATE_DATA, data, &argp->error);
if (ret)
goto e_free;
/* copy transport buffer to user space */
if (copy_to_user((void __user *)(uintptr_t)params.trans_uaddr,
trans_data, params.trans_len)) {
ret = -EFAULT;
goto e_free;
}
/* Copy packet header to userspace. */
ret = copy_to_user((void __user *)(uintptr_t)params.hdr_uaddr, hdr,
params.hdr_len);
e_free:
kfree(data);
e_free_trans_data:
kfree(trans_data);
e_free_hdr:
kfree(hdr);
e_unpin:
sev_unpin_memory(kvm, guest_page, n);
return ret;
}
int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
{
struct kvm_sev_cmd sev_cmd;
@ -1301,6 +1422,9 @@ int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
case KVM_SEV_SEND_START:
r = sev_send_start(kvm, &sev_cmd);
break;
case KVM_SEV_SEND_UPDATE_DATA:
r = sev_send_update_data(kvm, &sev_cmd);
break;
default:
r = -EINVAL;
goto out;
@ -1559,6 +1683,7 @@ void __init sev_hardware_setup(void)
/* Minimum ASID value that should be used for SEV guest */
min_sev_asid = edx;
sev_me_mask = 1UL << (ebx & 0x3f);
/* Initialize SEV ASID bitmaps */
sev_asid_bitmap = bitmap_zalloc(max_sev_asid, GFP_KERNEL);

9
include/uapi/linux/kvm.h
View File

@ -1744,6 +1744,15 @@ struct kvm_sev_send_start {
__u32 session_len;
};
struct kvm_sev_send_update_data {
__u64 hdr_uaddr;
__u32 hdr_len;
__u64 guest_uaddr;
__u32 guest_len;
__u64 trans_uaddr;
__u32 trans_len;
};
#define KVM_DEV_ASSIGN_ENABLE_IOMMU (1 << 0)
#define KVM_DEV_ASSIGN_PCI_2_3 (1 << 1)
#define KVM_DEV_ASSIGN_MASK_INTX (1 << 2)