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From: Joerg Roedel <jroedel@suse.de>
To: Arvind Sankar <nivedita@alum.mit.edu>
Cc: Joerg Roedel <joro@8bytes.org>,
	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 3/5] x86/boot/compressed/64: Check SEV encryption in 64-bit boot-path
Date: Tue, 20 Oct 2020 11:41:10 +0200	[thread overview]
Message-ID: <20201020094110.GG9328@suse.de> (raw)
In-Reply-To: <20201019212247.GA2815942@rani.riverdale.lan>

On Mon, Oct 19, 2020 at 05:22:47PM -0400, Arvind Sankar wrote:
> The boot cpu also enables CR4.PGE -- that code is shared between boot
> and secondary cpus. The boot cpu jumps to the first "1" label below,
> just before the call to sev_verify_cbit you're adding.

You are right, in the real kernel image PGE gets enabled early. I added
code to save and restore CR4 in sev_verify_cbit() and disable PGE during
the test.

Thanks,

	Joerg


  reply	other threads:[~2020-10-20  9:41 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-19 15:11 [PATCH 0/5] x86/sev-es: Mitigate some HV attack vectors Joerg Roedel
2020-10-19 15:11 ` [PATCH 1/5] x86/boot/compressed/64: Introduce sev_status Joerg Roedel
2020-10-20  0:59   ` Sean Christopherson
2020-10-20  1:08     ` Sean Christopherson
2020-10-20  9:55     ` Joerg Roedel
2020-10-19 15:11 ` [PATCH 2/5] x86/boot/compressed/64: Add CPUID sanity check to early #VC handler Joerg Roedel
2020-10-19 15:11 ` [PATCH 3/5] x86/boot/compressed/64: Check SEV encryption in 64-bit boot-path Joerg Roedel
2020-10-19 17:00   ` Arvind Sankar
2020-10-19 17:54     ` Arvind Sankar
2020-10-19 20:39       ` Joerg Roedel
2020-10-19 21:31         ` Arvind Sankar
2020-10-20  8:59           ` Joerg Roedel
2020-10-20 14:33             ` Arvind Sankar
2020-10-20 15:44               ` Joerg Roedel
2020-10-19 20:33     ` Joerg Roedel
2020-10-19 21:22       ` Arvind Sankar
2020-10-20  9:41         ` Joerg Roedel [this message]
2020-10-19 15:11 ` [PATCH 4/5] x86/head/64: Check SEV encryption before switching to kernel page-table Joerg Roedel
2020-10-19 15:11 ` [PATCH 5/5] x86/sev-es: Do not support MMIO to/from encrypted memory Joerg Roedel

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