[PATCH v13 05/12] KVM: SVM: Add KVM_SEV_RECEIVE_UPDATE_DATA command

Ashish Kalra
2021-04-15T15:55:32Z

From: Brijesh Singh <brijesh.singh@amd.com>

The command is used for copying the incoming buffer into the
SEV guest memory space.

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>
---
.../virt/kvm/amd-memory-encryption.rst | 24 ++++++
arch/x86/kvm/svm/sev.c | 79 +++++++++++++++++++
include/uapi/linux/kvm.h | 9 +++
3 files changed, 112 insertions(+)

diff --git a/Documentation/virt/kvm/amd-memory-encryption.rst b/Documentation/virt/kvm/amd-memory-encryption.rst
index c86c1ded8dd8..c6ed5b26d841 100644
--- a/Documentation/virt/kvm/amd-memory-encryption.rst
+++ b/Documentation/virt/kvm/amd-memory-encryption.rst
@@ -372,6 +372,30 @@ On success, the 'handle' field contains a new handle and on error, a negative va

For more details, see SEV spec Section 6.12.

+14. KVM_SEV_RECEIVE_UPDATE_DATA
+----------------------------
+
+The KVM_SEV_RECEIVE_UPDATE_DATA command can be used by the hypervisor to copy
+the incoming buffers into the guest memory region with encryption context
+created during the KVM_SEV_RECEIVE_START.
+
+Parameters (in): struct kvm_sev_receive_update_data
+
+Returns: 0 on success, -negative on error
+
+::
+
+ struct kvm_sev_launch_receive_update_data {
+ __u64 hdr_uaddr; /* userspace address containing the packet header */
+ __u32 hdr_len;
+
+ __u64 guest_uaddr; /* the destination guest memory region */
+ __u32 guest_len;
+
+ __u64 trans_uaddr; /* the incoming buffer memory region */
+ __u32 trans_len;
+ };
+
References
==========

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index e530c2b34b5e..2c95657cc9bf 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -1448,6 +1448,82 @@ static int sev_receive_start(struct kvm *kvm, struct kvm_sev_cmd *argp)
return ret;
}

+static int sev_receive_update_data(struct kvm *kvm, struct kvm_sev_cmd *argp)
+{
+ struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
+ struct kvm_sev_receive_update_data params;
+ struct sev_data_receive_update_data *data;
+ void *hdr = NULL, *trans = NULL;
+ struct page **guest_page;
+ unsigned long n;
+ int ret, offset;
+
+ if (!sev_guest(kvm))
+ return -EINVAL;
+
+ if (copy_from_user(&params, (void __user *)(uintptr_t)argp->data,
+ sizeof(struct kvm_sev_receive_update_data)))
+ return -EFAULT;
+
+ if (!params.hdr_uaddr || !params.hdr_len ||
+ !params.guest_uaddr || !params.guest_len ||
+ !params.trans_uaddr || !params.trans_len)
+ 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;
+
+ hdr = psp_copy_user_blob(params.hdr_uaddr, params.hdr_len);
+ if (IS_ERR(hdr))
+ return PTR_ERR(hdr);
+
+ trans = psp_copy_user_blob(params.trans_uaddr, params.trans_len);
+ if (IS_ERR(trans)) {
+ ret = PTR_ERR(trans);
+ goto e_free_hdr;
+ }
+
+ ret = -ENOMEM;
+ data = kzalloc(sizeof(*data), GFP_KERNEL);
+ if (!data)
+ goto e_free_trans;
+
+ data->hdr_address = __psp_pa(hdr);
+ data->hdr_len = params.hdr_len;
+ data->trans_address = __psp_pa(trans);
+ data->trans_len = params.trans_len;
+
+ /* Pin guest memory */
+ ret = -EFAULT;
+ guest_page = sev_pin_memory(kvm, params.guest_uaddr & PAGE_MASK,
+ PAGE_SIZE, &n, 0);
+ if (!guest_page)
+ goto e_free;
+
+ /* The RECEIVE_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_RECEIVE_UPDATE_DATA, data,
+ &argp->error);
+
+ sev_unpin_memory(kvm, guest_page, n);
+
+e_free:
+ kfree(data);
+e_free_trans:
+ kfree(trans);
+e_free_hdr:
+ kfree(hdr);
+
+ return ret;
+}
+
int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
{
struct kvm_sev_cmd sev_cmd;
@@ -1513,6 +1589,9 @@ int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
case KVM_SEV_RECEIVE_START:
r = sev_receive_start(kvm, &sev_cmd);
break;
+ case KVM_SEV_RECEIVE_UPDATE_DATA:
+ r = sev_receive_update_data(kvm, &sev_cmd);
+ break;
default:
r = -EINVAL;
goto out;
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 29c25e641a0c..3a656d43fc6c 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -1759,6 +1759,15 @@ struct kvm_sev_receive_start {
__u32 session_len;
};

+struct kvm_sev_receive_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)
--
2.17.1