Re: [edk2-devel] [PATCH] OvmfPkg/XenPlatformPei: Relocate shared_info page mapping

["Laszlo Ersek" <lersek@redhat.com>]

On 06/28/21 15:23, Anthony PERARD via groups.io wrote:
> From: Anthony PERARD <anthony.perard@citrix.com>
> 
> Unfortunately, Xen isn't ready to deal with mapping at the top of the
> physical address space, so we relocate the mapping after the LAPIC
> location.
> 
> See this thread about the issue with the mapping:
> - https://lore.kernel.org/xen-devel/f8c4151a-6dac-d87c-ef46-eb35ada07bd9@suse.com/
> 
> The PhysicalAddressIdentityMapping() call isn't going to do anything
> anymore since everything under 4GB is already mapped, but there is no
> need to remove the call.
> 
> CC: Jan Beulich <JBeulich@suse.com>
> CC: Andrew Cooper <andrew.cooper3@citrix.com>
> Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
> ---
>  OvmfPkg/XenPlatformPei/Xen.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/OvmfPkg/XenPlatformPei/Xen.c b/OvmfPkg/XenPlatformPei/Xen.c
> index a4e82b356936..9c6641895970 100644
> --- a/OvmfPkg/XenPlatformPei/Xen.c
> +++ b/OvmfPkg/XenPlatformPei/Xen.c
> @@ -569,7 +569,7 @@ CalibrateLapicTimer (
>    EFI_STATUS            Status;
>  
>  
> -  SharedInfo = (VOID*)((1ULL << mPhysMemAddressWidth) - EFI_PAGE_SIZE);
> +  SharedInfo = (VOID*)((UINTN)PcdGet32 (PcdCpuLocalApicBaseAddress) + SIZE_1MB);
>    Status = PhysicalAddressIdentityMapping ((EFI_PHYSICAL_ADDRESS)SharedInfo);
>    if (EFI_ERROR (Status)) {
>      DEBUG ((DEBUG_ERROR,
> 

Acked-by: Laszlo Ersek <lersek@redhat.com>

I guess I should merge this after Jan and/or Andrew ack it.

Thanks
Laszlo