Re: [PATCH v12 26/29] KVM: SEV: Provide support for SNP_GUEST_REQUEST NAE event

[Tom Lendacky <thomas.lendacky@amd.com>]

On 3/29/24 17:58, Michael Roth wrote:
> From: Brijesh Singh <brijesh.singh@amd.com>
> 
> Version 2 of GHCB specification added support for the SNP Guest Request
> Message NAE event. The event allows for an SEV-SNP guest to make
> requests to the SEV-SNP firmware through hypervisor using the
> SNP_GUEST_REQUEST API defined in the SEV-SNP firmware specification.
> 
> This is used by guests primarily to request attestation reports from
> firmware. There are other request types are available as well, but the
> specifics of what guest requests are being made are opaque to the
> hypervisor, which only serves as a proxy for the guest requests and
> firmware responses.
> 
> Implement handling for these events.
> 
> Co-developed-by: Alexey Kardashevskiy <aik@amd.com>
> Signed-off-by: Alexey Kardashevskiy <aik@amd.com>
> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
> Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>

You need to add a Co-developed-by: for Asish here.

> [mdr: ensure FW command failures are indicated to guest, drop extended
>   request handling to be re-written as separate patch, massage commit]
> Signed-off-by: Michael Roth <michael.roth@amd.com>

One minor comment below should another version be required, otherwise:

Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>

> ---
>   arch/x86/kvm/svm/sev.c         | 83 ++++++++++++++++++++++++++++++++++
>   include/uapi/linux/sev-guest.h |  9 ++++
>   2 files changed, 92 insertions(+)
> 
> diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
> index 658116537f3f..f56f04553e81 100644
> --- a/arch/x86/kvm/svm/sev.c
> +++ b/arch/x86/kvm/svm/sev.c

>   
> +static bool snp_setup_guest_buf(struct kvm *kvm, struct sev_data_snp_guest_request *data,
> +				gpa_t req_gpa, gpa_t resp_gpa)
> +{
> +	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
> +	kvm_pfn_t req_pfn, resp_pfn;
> +
> +	if (!IS_ALIGNED(req_gpa, PAGE_SIZE) || !IS_ALIGNED(resp_gpa, PAGE_SIZE))

Minor, but you can use PAGE_ALIGNED() here.

Thanks,
Tom

> +		return false;