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From: Joerg Roedel <joro@8bytes.org>
To: Arvind Sankar <nivedita@alum.mit.edu>
Cc: Joerg Roedel <jroedel@suse.de>,
	x86@kernel.org, Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Andy Lutomirski <luto@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Kees Cook <keescook@chromium.org>,
	Martin Radev <martin.b.radev@gmail.com>,
	Tom Lendacky <thomas.lendacky@amd.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 3/5] x86/boot/compressed/64: Check SEV encryption in 64-bit boot-path
Date: Wed, 21 Oct 2020 14:49:46 +0200	[thread overview]
Message-ID: <20201021124946.GA30514@8bytes.org> (raw)
In-Reply-To: <20201020160428.GA3233355@rani.riverdale.lan>

On Tue, Oct 20, 2020 at 12:04:28PM -0400, Arvind Sankar wrote:
> This is called from both assembly and C, but anyway, you're already
> assuming r10 and r11 can be clobbered safely, and you just took out the
> save/restores in set_sev_encryption_mask, which is actually called only
> from assembly.

Alright, maybe I was a bit too caucious. I changed the CR4 handling to
use %r8 and %r9 instead, which are also clobbered.

Regards,

	Joerg

  reply	other threads:[~2020-10-21 12:49 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-20 12:18 [PATCH v2 0/5] x86/sev-es: Mitigate some HV attack vectors Joerg Roedel
2020-10-20 12:18 ` [PATCH v2 1/5] x86/boot/compressed/64: Introduce sev_status Joerg Roedel
2020-10-20 12:18 ` [PATCH v2 2/5] x86/boot/compressed/64: Add CPUID sanity check to early #VC handler Joerg Roedel
2020-10-20 12:18 ` [PATCH v2 3/5] x86/boot/compressed/64: Check SEV encryption in 64-bit boot-path Joerg Roedel
2020-10-20 14:12   ` Arvind Sankar
2020-10-20 15:48     ` Joerg Roedel
2020-10-20 16:04       ` Arvind Sankar
2020-10-21 12:49         ` Joerg Roedel [this message]
2020-10-20 12:18 ` [PATCH v2 4/5] x86/head/64: Check SEV encryption before switching to kernel page-table Joerg Roedel
2020-10-20 12:18 ` [PATCH v2 5/5] x86/sev-es: Do not support MMIO to/from encrypted memory Joerg Roedel

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