Re: [PATCH] arm/efi: fix ram base detection

From: "Vincent Stehlé" <vincent.stehle@laposte.net>
To: Leif Lindholm <leif@nuviainc.com>
Cc: Daniel Kiper <dkiper@net-space.pl>,
	grub-devel@gnu.org, Grant Likely <grant.likely@arm.com>,
	Peter Jones <pjones@redhat.com>
Subject: Re: [PATCH] arm/efi: fix ram base detection
Date: Tue, 30 Mar 2021 22:01:23 +0200	[thread overview]
Message-ID: <YGODk/UWCg5JJvBR@romuald.bergerie> (raw)
In-Reply-To: <20210322182851.GY1664@vanye>

On Mon, Mar 22, 2021 at 06:28:51PM +0000, Leif Lindholm wrote:
..
> > > diff --git a/grub-core/kern/efi/mm.c b/grub-core/kern/efi/mm.c
> > > index 0cdb063bb..abf8772bc 100644
> > > --- a/grub-core/kern/efi/mm.c
> > > +++ b/grub-core/kern/efi/mm.c
> > > @@ -677,7 +677,8 @@ grub_efi_get_ram_base(grub_addr_t *base_addr)
> > >    for (desc = memory_map, *base_addr = GRUB_EFI_MAX_USABLE_ADDRESS;
> > >         (grub_addr_t) desc < ((grub_addr_t) memory_map + memory_map_size);
> > >         desc = NEXT_MEMORY_DESCRIPTOR (desc, desc_size))
> > > -    if (desc->attribute & GRUB_EFI_MEMORY_WB)
> > > +    if (desc->type == GRUB_EFI_CONVENTIONAL_MEMORY &&
> > > +        desc->attribute & GRUB_EFI_MEMORY_WB)
> 
> Can we safely assume we don't also need to check against
> GRUB_EFI_PERSISTENT_MEMORY? If so, this is fine.

Hi Leif,

Thanks for the review.

This is a good question about persistent memory; I don't know if we should
check it or not.

I am "fighting" with qemu to add an nvdimm above or below the first normal
memory region to see how this behaves. I will let you know when I have
succeeded.

Best regards,
Vincent.