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From: Tom Lendacky <thomas.lendacky@amd.com>
To: Dov Murik <dovmurik@linux.ibm.com>, qemu-devel@nongnu.org
Cc: "James Bottomley" <jejb@linux.ibm.com>,
	"Daniel P. Berrangé" <berrange@redhat.com>,
	"Michael S. Tsirkin" <mst@redhat.com>,
	"Marcel Apfelbaum" <marcel.apfelbaum@gmail.com>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Dr. David Alan Gilbert" <dgilbert@redhat.com>,
	"Richard Henderson" <richard.henderson@linaro.org>,
	"Eduardo Habkost" <ehabkost@redhat.com>,
	"Connor Kuehl" <ckuehl@redhat.com>,
	"Philippe Mathieu-Daudé" <philmd@redhat.com>,
	"Laszlo Ersek" <lersek@redhat.com>,
	"Ashish Kalra" <ashish.kalra@amd.com>,
	"Brijesh Singh" <brijesh.singh@amd.com>,
	"Tobin Feldman-Fitzthum" <tobin@linux.ibm.com>,
	"Jim Cadden" <jcadden@ibm.com>,
	"Hubertus Franke" <frankeh@us.ibm.com>
Subject: Re: [PATCH v4 1/2] sev/i386: Introduce sev_add_kernel_loader_hashes for measured linux boot
Date: Mon, 18 Oct 2021 13:02:37 -0500	[thread overview]
Message-ID: <3b9d10d9-5d9c-da52-f18c-cd93c1931706@amd.com> (raw)
In-Reply-To: <20210930054915.13252-2-dovmurik@linux.ibm.com>

On 9/30/21 12:49 AM, Dov Murik wrote:

...

> +/*
> + * Add the hashes of the linux kernel/initrd/cmdline to an encrypted guest page
> + * which is included in SEV's initial memory measurement.
> + */
> +bool sev_add_kernel_loader_hashes(SevKernelLoaderContext *ctx, Error **errp)
> +{
> +    uint8_t *data;
> +    SevHashTableDescriptor *area;
> +    SevHashTable *ht;
> +    uint8_t cmdline_hash[HASH_SIZE];
> +    uint8_t initrd_hash[HASH_SIZE];
> +    uint8_t kernel_hash[HASH_SIZE];
> +    uint8_t *hashp;
> +    size_t hash_len = HASH_SIZE;
> +    int aligned_len;
> +
> +    if (!pc_system_ovmf_table_find(SEV_HASH_TABLE_RV_GUID, &data, NULL)) {
> +        error_setg(errp, "SEV: kernel specified but OVMF has no hash table guid");
> +        return false;
> +    }

This breaks backwards compatibility with an older OVMF image. Any older 
OVMF image with SEV support that doesn't have the hash table GUID will now 
fail to boot using -kernel/-initrd/-append, where it used to be able to 
boot before.

Is that anything we need to be concerned about?

Thanks,
Tom



  parent reply	other threads:[~2021-10-18 18:09 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-30  5:49 [PATCH v4 0/2] x86/sev: Measured Linux SEV guest with kernel/initrd/cmdline Dov Murik
2021-09-30  5:49 ` [PATCH v4 1/2] sev/i386: Introduce sev_add_kernel_loader_hashes for measured linux boot Dov Murik
2021-09-30  8:32   ` Daniel P. Berrangé
2021-09-30 10:13     ` Dov Murik
2021-10-18 18:02   ` Tom Lendacky [this message]
2021-10-19  6:18     ` Dov Murik
2021-10-20 15:26       ` Tom Lendacky
2021-10-27 19:43         ` Brijesh Singh
2021-10-28  8:41           ` Dov Murik
2021-11-01 10:28             ` Dov Murik
2021-09-30  5:49 ` [PATCH v4 2/2] x86/sev: generate SEV kernel loader hashes in x86_load_linux Dov Murik
2021-10-04  8:03 ` [PATCH v4 0/2] x86/sev: Measured Linux SEV guest with kernel/initrd/cmdline Paolo Bonzini
2021-10-04 17:23   ` Dov Murik

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