Re: [PATCH v7 1/3] efi/x86: Fix EFI memory map corruption with kexec

[Mike Rapoport <rppt@kernel.org>]

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.