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From:   Dionna Amalie Glaze <dionnaglaze@google.com>
Date:   Thu, 19 Jan 2023 12:35:52 -0800
Message-ID: <CAAH4kHYoWtM=Xe0kgmtKw01-45DefEikdLz0qUJRRMLdZHzkwA@mail.gmail.com>
Subject: Re: [PATCH RFC v7 52/64] KVM: SVM: Provide support for
 SNP_GUEST_REQUEST NAE event
To:     Michael Roth <michael.roth@amd.com>
Cc:     kvm@vger.kernel.org, linux-coco@lists.linux.dev,
        linux-mm@kvack.org, linux-crypto@vger.kernel.org, x86@kernel.org,
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        jroedel@suse.de, thomas.lendacky@amd.com, hpa@zytor.com,
        ardb@kernel.org, pbonzini@redhat.com, seanjc@google.com,
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        dgilbert@redhat.com, jarkko@kernel.org, ashish.kalra@amd.com,
        harald@profian.com, Brijesh Singh <brijesh.singh@amd.com>
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Precedence: bulk

> +
> +static void snp_handle_guest_request(struct vcpu_svm *svm, gpa_t req_gpa, gpa_t resp_gpa)
> +{

Both regular,

> +
> +static void snp_handle_ext_guest_request(struct vcpu_svm *svm, gpa_t req_gpa, gpa_t resp_gpa)
> +{

and extended guest requests should be subject to rate limiting, since
they take a lock on the shared resource that is the AMD-SP (psp?). I
proposed a mechanism with empirically chosen defaults in

[PATCH v2 0/2] kvm: sev: Add SNP guest request throttling
[PATCH v2 1/2] kvm: sev: Add SEV-SNP guest request throttling
[PATCH v2 2/2] kvm: sev: If ccp is busy, report throttled to guest

http://129.79.113.48/hypermail/linux/kernel/2211.2/03107.html
http://129.79.113.48/hypermail/linux/kernel/2211.2/03110.html
http://129.79.113.48/hypermail/linux/kernel/2211.2/03111.html

But I don't see these on lore. Would you like me to repost these?

-- 
-Dionna Glaze, PhD (she/her)