From: Paolo Bonzini <pbonzini@redhat.com>
To: Ashish Kalra <Ashish.Kalra@amd.com>
Cc: seanjc@google.com, tglx@linutronix.de, bp@alien8.de,
mingo@redhat.com, hpa@zytor.com, joro@8bytes.org,
Thomas.Lendacky@amd.com, x86@kernel.org, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org, srutherford@google.com,
brijesh.singh@amd.com
Subject: Re: [PATCH] KVM: SVM: Fix SEV SEND_START session length & SEND_UPDATE_DATA query length after commit 238eca821cee
Date: Tue, 8 Jun 2021 18:22:14 +0200 [thread overview]
Message-ID: <c579735c-31c3-eed5-576f-b07177231790@redhat.com> (raw)
In-Reply-To: <20210607061532.27459-1-Ashish.Kalra@amd.com>
On 07/06/21 08:15, Ashish Kalra wrote:
> From: Ashish Kalra <ashish.kalra@amd.com>
>
> Commit 238eca821cee ("KVM: SVM: Allocate SEV command structures on local stack")
> uses the local stack to allocate the structures used to communicate with the PSP,
> which were earlier being kzalloced. This breaks SEV live migration for
> computing the SEND_START session length and SEND_UPDATE_DATA query length as
> session_len and trans_len and hdr_len fields are not zeroed respectively for
> the above commands before issuing the SEV Firmware API call, hence the
> firmware returns incorrect session length and update data header or trans length.
>
> Also the SEV Firmware API returns SEV_RET_INVALID_LEN firmware error
> for these length query API calls, and the return value and the
> firmware error needs to be passed to the userspace as it is, so
> need to remove the return check in the KVM code.
>
> Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
> ---
> arch/x86/kvm/svm/sev.c | 6 ++----
> 1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
> index 5bc887e9a986..e0ce5da97fc2 100644
> --- a/arch/x86/kvm/svm/sev.c
> +++ b/arch/x86/kvm/svm/sev.c
> @@ -1103,10 +1103,9 @@ __sev_send_start_query_session_length(struct kvm *kvm, struct kvm_sev_cmd *argp,
> struct sev_data_send_start data;
> int ret;
>
> + memset(&data, 0, sizeof(data));
> data.handle = sev->handle;
> ret = sev_issue_cmd(kvm, SEV_CMD_SEND_START, &data, &argp->error);
> - if (ret < 0)
> - return ret;
>
> params->session_len = data.session_len;
> if (copy_to_user((void __user *)(uintptr_t)argp->data, params,
> @@ -1215,10 +1214,9 @@ __sev_send_update_data_query_lengths(struct kvm *kvm, struct kvm_sev_cmd *argp,
> struct sev_data_send_update_data data;
> int ret;
>
> + memset(&data, 0, sizeof(data));
> data.handle = sev->handle;
> ret = sev_issue_cmd(kvm, SEV_CMD_SEND_UPDATE_DATA, &data, &argp->error);
> - if (ret < 0)
> - return ret;
>
> params->hdr_len = data.hdr_len;
> params->trans_len = data.trans_len;
>
Queued, thanks.
Paolo
prev parent reply other threads:[~2021-06-08 16:22 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-07 6:15 [PATCH] KVM: SVM: Fix SEV SEND_START session length & SEND_UPDATE_DATA query length after commit 238eca821cee Ashish Kalra
2021-06-08 16:22 ` Paolo Bonzini [this message]
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