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Date:   Fri, 4 Feb 2022 17:21:51 +0100
From:   Borislav Petkov <bp@alien8.de>
To:     Brijesh Singh <brijesh.singh@amd.com>
Cc:     x86@kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
        linux-efi@vger.kernel.org, platform-driver-x86@vger.kernel.org,
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        "H. Peter Anvin" <hpa@zytor.com>, Ard Biesheuvel <ardb@kernel.org>,
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        David Rientjes <rientjes@google.com>,
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        Tobin Feldman-Fitzthum <tobin@ibm.com>,
        Michael Roth <michael.roth@amd.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        "Kirill A . Shutemov" <kirill@shutemov.name>,
        Andi Kleen <ak@linux.intel.com>,
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        brijesh.ksingh@gmail.com, tony.luck@intel.com, marcorr@google.com,
        sathyanarayanan.kuppuswamy@linux.intel.com
Subject: Re: [PATCH v9 29/43] x86/boot: Add Confidential Computing type to
 setup_data
Message-ID: <Yf1Sn4AdPgIzpih9@zn.tnic>
References: <20220128171804.569796-1-brijesh.singh@amd.com>
 <20220128171804.569796-30-brijesh.singh@amd.com>
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On Fri, Jan 28, 2022 at 11:17:50AM -0600, Brijesh Singh wrote:
> +/*
> + * AMD SEV Confidential computing blob structure. The structure is
> + * defined in OVMF UEFI firmware header:
> + * https://github.com/tianocore/edk2/blob/master/OvmfPkg/Include/Guid/ConfidentialComputingSevSnpBlob.h

So looking at that typedef struct CONFIDENTIAL_COMPUTING_SNP_BLOB_LOCATION there:

typedef struct {
  UINT32    Header;
  UINT16    Version;
  UINT16    Reserved1;
  UINT64    SecretsPhysicalAddress;
  UINT32    SecretsSize;
  UINT64    CpuidPhysicalAddress;
  UINT32    CpuidLSize;
} CONFIDENTIAL_COMPUTING_SNP_BLOB_LOCATION;

> + */
> +#define CC_BLOB_SEV_HDR_MAGIC	0x45444d41
> +struct cc_blob_sev_info {
> +	u32 magic;

That's called "Header" there.

> +	u16 version;
> +	u16 reserved;
> +	u64 secrets_phys;
> +	u32 secrets_len;
> +	u32 rsvd1;

You've added that member for padding but the fw blob one doesn't have
it.

But if we get a blob from the firmware and the structure layout differs,
how is this supposed to even work?

> +	u64 cpuid_phys;
> +	u32 cpuid_len;
> +	u32 rsvd2;

That one too.

Or are you going to change the blob layout in ovmf too, to match?

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette