linux-kernel - Re: [RFC] efi: Add ACPI_MEMORY

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Date: Mon, 19 Feb 2024 20:09:44 -0800
From: Boqun Feng <boqun.feng@...il.com>
To: Greg KH <gregkh@...uxfoundation.org>
Cc: linux-arm-kernel@...r.kernel.org, stable@...r.kernel.org,
	Ard Biesheuvel <ardb@...nel.org>, linux-efi@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Oliver Smith-Denny <osde@...ux.microsoft.com>
Subject: Re: [RFC] efi: Add ACPI_MEMORY_NVS into the linear map

On Sat, Feb 17, 2024 at 08:49:32AM +0100, Greg KH wrote:
> On Thu, Feb 15, 2024 at 02:51:06PM -0800, Boqun Feng wrote:
> > Currently ACPI_MEMORY_NVS is omitted from the linear map, which causes
> > a trouble with the following firmware memory region setup:
> > 
> > 	[..] efi:   0x0000dfd62000-0x0000dfd83fff [ACPI Reclaim|...]
> > 	[..] efi:   0x0000dfd84000-0x0000dfd87fff [ACPI Mem NVS|...]
> > 
> > , on ARM64 with 64k page size, the whole 0x0000dfd80000-0x0000dfd8ffff
> > range will be omitted from the the linear map due to 64k round-up. And
> > a page fault happens when trying to access the ACPI_RECLAIM_MEMORY:
> > 
> > 	[...] Unable to handle kernel paging request at virtual address ffff0000dfd80000
> > 
> > To fix this, add ACPI_MEMORY_NVS into the linear map.
> > 
> > Signed-off-by: Boqun Feng <boqun.feng@...il.com>
> > Cc: stable@...r.kernel.org # 5.15+
> 
> What commit id does this fix?  Can you include that as well?
> 

It should be 7aff79e297ee ("Drivers: hv: Enable Hyper-V code to be built
on ARM64"), but as Ard mentioned earlier, this could be fixed at the VM
firmware, and Oliver is working on that. Should the situation change, I
will send a V2 with more information and include the commit id.

Regards,
Boqun

> thanks,
> 
> greg k-h