linux-kernel - Re: [PATCH v2 2/2] x86/sev: let sev_es_efi_map

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Message-ID: <4kk67edghl7wvqzuyubgr45mhols37yqsorbxxvkypm3xwnuvc@2oek5mladprs>
Date: Wed, 25 Jun 2025 15:21:47 +0200
From: Gerd Hoffmann <kraxel@...hat.com>
To: Borislav Petkov <bp@...en8.de>
Cc: linux-coco@...ts.linux.dev, kvm@...r.kernel.org, 
	Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>, 
	Dave Hansen <dave.hansen@...ux.intel.com>, 
	"maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" <x86@...nel.org>, "H. Peter Anvin" <hpa@...or.com>, 
	Ard Biesheuvel <ardb@...nel.org>, 
	"open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)" <linux-kernel@...r.kernel.org>, 
	"open list:EXTENSIBLE FIRMWARE INTERFACE (EFI)" <linux-efi@...r.kernel.org>
Subject: Re: [PATCH v2 2/2] x86/sev: let sev_es_efi_map_ghcbs map the caa
 pages too

On Wed, Jun 25, 2025 at 02:40:16PM +0200, Borislav Petkov wrote:
> On Wed, Jun 25, 2025 at 01:52:58PM +0200, Gerd Hoffmann wrote:
> > The kernel allocates the caa page(s) only when running under svsm, see
> > alloc_runtime_data(), so this is not correct.  I think we either have to
> > return to the original behavior of only doing something in case address
> > is not NULL
> 
> Yes, we're doing something only when the address is not NULL.

This is inside a loop, so returning in case the caa address is NULL will
skip ghcb setup for all but the first CPU.

take care,
  Gerd