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Date: Mon, 6 Apr 2020 17:49:53 -0700
From: Steve Rutherford <srutherford@...gle.com>
To: Venu Busireddy <venu.busireddy@...cle.com>
Cc: Ashish Kalra <Ashish.Kalra@....com>,
Paolo Bonzini <pbonzini@...hat.com>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>,
"H. Peter Anvin" <hpa@...or.com>, Joerg Roedel <joro@...tes.org>,
Borislav Petkov <bp@...e.de>,
Tom Lendacky <thomas.lendacky@....com>,
X86 ML <x86@...nel.org>, KVM list <kvm@...r.kernel.org>,
LKML <linux-kernel@...r.kernel.org>,
David Rientjes <rientjes@...gle.com>,
Andy Lutomirski <luto@...nel.org>,
Brijesh Singh <brijesh.singh@....com>
Subject: Re: [PATCH v6 05/14] KVM: SVM: Add KVM_SEV_RECEIVE_UPDATE_DATA command
On Thu, Apr 2, 2020 at 3:31 PM Venu Busireddy <venu.busireddy@...cle.com> wrote:
>
> On 2020-03-30 06:21:20 +0000, Ashish Kalra wrote:
> > From: Brijesh Singh <Brijesh.Singh@....com>
> >
> > The command is used for copying the incoming buffer into the
> > SEV guest memory space.
> >
> > 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>
> > Signed-off-by: Ashish Kalra <ashish.kalra@....com>
>
> Reviewed-by: Venu Busireddy <venu.busireddy@...cle.com>
>
> > ---
> > .../virt/kvm/amd-memory-encryption.rst | 24 ++++++
> > arch/x86/kvm/svm.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 ef1f1f3a5b40..554aa33a99cc 100644
> > --- a/Documentation/virt/kvm/amd-memory-encryption.rst
> > +++ b/Documentation/virt/kvm/amd-memory-encryption.rst
> > @@ -351,6 +351,30 @@ 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.c b/arch/x86/kvm/svm.c
> > index 038b47685733..5fc5355536d7 100644
> > --- a/arch/x86/kvm/svm.c
> > +++ b/arch/x86/kvm/svm.c
> > @@ -7497,6 +7497,82 @@ 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(¶ms, (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;
Check for overflow.
>
> > +
> > + 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;
> > +}
> > +
> > static int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
> > {
> > struct kvm_sev_cmd sev_cmd;
> > @@ -7553,6 +7629,9 @@ static 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 74764b9db5fa..4e80c57a3182 100644
> > --- a/include/uapi/linux/kvm.h
> > +++ b/include/uapi/linux/kvm.h
> > @@ -1588,6 +1588,15 @@ 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
> >
Otherwise looks fine to my eye.
Reviewed-by: Steve Rutherford <srutherford@...gle.com>
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