Received-SPF: pass (google.com: domain of linux-kernel+bounces-199370-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45e3:2400::1 as permitted sender) client-ip=2604:1380:45e3:2400::1;
Date: Mon, 3 Jun 2024 18:31:13 +0300
From: Mike Rapoport <rppt@kernel.org>
To: Borislav Petkov <bp@alien8.de>
Cc: "Kalra, Ashish" <ashish.kalra@amd.com>, tglx@linutronix.de,
	mingo@redhat.com, dave.hansen@linux.intel.com, x86@kernel.org,
	rafael@kernel.org, hpa@zytor.com, peterz@infradead.org,
	adrian.hunter@intel.com, sathyanarayanan.kuppuswamy@linux.intel.com,
	jun.nakajima@intel.com, rick.p.edgecombe@intel.com,
	thomas.lendacky@amd.com, michael.roth@amd.com, seanjc@google.com,
	kai.huang@intel.com, bhe@redhat.com,
	kirill.shutemov@linux.intel.com, bdas@redhat.com,
	vkuznets@redhat.com, dionnaglaze@google.com, anisinha@redhat.com,
	jroedel@suse.de, ardb@kernel.org, kexec@lists.infradead.org,
	linux-coco@lists.linux.dev, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v7 1/3] efi/x86: Fix EFI memory map corruption with kexec
Message-ID: <Zl3hwYL2GDiyUfGo@kernel.org>
References: <20240528095522.509667-1-kirill.shutemov@linux.intel.com>
 <cover.1717111180.git.ashish.kalra@amd.com>
 <f4be03b8488665f56a1e5c6e6459f447352dfcf5.1717111180.git.ashish.kalra@amd.com>
 <20240603085654.GBZl2FVjPd-gagt-UA@fat_crate.local>
 <8e3dfc15-f609-4839-85c7-1cc8cefd7acc@amd.com>
 <Zl3HfiQ6oHdTdOdA@kernel.org>
 <1ef36309-8d7f-447b-a54a-3cdafeccca64@amd.com>
 <20240603144639.GCZl3XTwmFHwi-KUZW@fat_crate.local>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20240603144639.GCZl3XTwmFHwi-KUZW@fat_crate.local>

On Mon, Jun 03, 2024 at 04:46:39PM +0200, Borislav Petkov wrote:
> On Mon, Jun 03, 2024 at 09:01:49AM -0500, Kalra, Ashish wrote:
> > If we skip efi_arch_mem_reserve() (which should probably be anyway skipped
> > for kexec case), then for kexec boot, EFI memmap is memremapped in the same
> > virtual address as the first kernel and not the allocated memblock address.
> 
> Are you saying that we should simply do
> 
> diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
> index fdf07dd6f459..410cb0743289 100644
> --- a/drivers/firmware/efi/efi.c
> +++ b/drivers/firmware/efi/efi.c
> @@ -577,6 +577,9 @@ void __init efi_mem_reserve(phys_addr_t addr, u64 size)
>  	if (WARN_ON_ONCE(efi_enabled(EFI_PARAVIRT)))
>  		return;
>  
> +	if (kexec_in_progress)
> +		return;
> +
>  	if (!memblock_is_region_reserved(addr, size))
>  		memblock_reserve(addr, size);
>  
> and skip that whole call?

I think Ashish suggested rather 

diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index fdf07dd6f459..eccc10ab15a4 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -580,6 +580,9 @@ void __init efi_mem_reserve(phys_addr_t addr, u64 size)
 	if (!memblock_is_region_reserved(addr, size))
 		memblock_reserve(addr, size);
 
+	if (kexec_in_progress)
+		return;
+
 	/*
 	 * Some architectures (x86) reserve all boot services ranges
 	 * until efi_free_boot_services() because of buggy firmware
 
> -- 
> Regards/Gruss,
>     Boris.
> 
> https://people.kernel.org/tglx/notes-about-netiquette

-- 
Sincerely yours,
Mike.