linux-kernel - Re: [PATCH v11 14/20] x86/sev: Add Secure TSC support for SNP guests

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <a98c1ab8-ea15-4a31-9246-754675e13928@amd.com>
Date: Fri, 13 Sep 2024 11:29:03 -0500
From: Tom Lendacky <thomas.lendacky@....com>
To: Nikunj A Dadhania <nikunj@....com>, linux-kernel@...r.kernel.org,
 bp@...en8.de, x86@...nel.org, kvm@...r.kernel.org
Cc: mingo@...hat.com, tglx@...utronix.de, dave.hansen@...ux.intel.com,
 pgonda@...gle.com, seanjc@...gle.com, pbonzini@...hat.com
Subject: Re: [PATCH v11 14/20] x86/sev: Add Secure TSC support for SNP guests

On 7/31/24 10:08, Nikunj A Dadhania wrote:
> Add support for Secure TSC in SNP-enabled guests. Secure TSC allows guests
> to securely use RDTSC/RDTSCP instructions, ensuring that the parameters
> used cannot be altered by the hypervisor once the guest is launched.
> 
> Secure TSC-enabled guests need to query TSC information from the AMD
> Security Processor. This communication channel is encrypted between the AMD
> Security Processor and the guest, with the hypervisor acting merely as a
> conduit to deliver the guest messages to the AMD Security Processor. Each
> message is protected with AEAD (AES-256 GCM). Use a minimal AES GCM library
> to encrypt and decrypt SNP guest messages for communication with the PSP.
> 
> Use mem_encrypt_init() to fetch SNP TSC information from the AMD Security
> Processor and initialize snp_tsc_scale and snp_tsc_offset. During secondary
> CPU initialization, set the VMSA fields GUEST_TSC_SCALE (offset 2F0h) and
> GUEST_TSC_OFFSET (offset 2F8h) with snp_tsc_scale and snp_tsc_offset,
> respectively.
> 
> Since handle_guest_request() is common routine used by both the SEV guest
> driver and Secure TSC code, move it to the SEV header file.
> 
> Signed-off-by: Nikunj A Dadhania <nikunj@....com>
> Tested-by: Peter Gonda <pgonda@...gle.com>

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

> ---
>  arch/x86/include/asm/sev-common.h       |  1 +
>  arch/x86/include/asm/sev.h              | 46 +++++++++++++
>  arch/x86/include/asm/svm.h              |  6 +-
>  arch/x86/coco/sev/core.c                | 91 +++++++++++++++++++++++++
>  arch/x86/mm/mem_encrypt.c               |  4 ++
>  drivers/virt/coco/sev-guest/sev-guest.c | 19 ------
>  6 files changed, 146 insertions(+), 21 deletions(-)
>