Re: [edk2-devel] [PATCH 1/1] OvmfPkg/XenPvBlkDxe: Fix memory barrier macro

2022-07-21 Thread Andrew Cooper via groups.io
On 19/07/2022 14:52, Anthony Perard wrote: > diff --git a/OvmfPkg/XenPvBlkDxe/XenPvBlkDxe.h > b/OvmfPkg/XenPvBlkDxe/XenPvBlkDxe.h > index 350b7bd309c0..67ee1899e9a8 100644 > --- a/OvmfPkg/XenPvBlkDxe/XenPvBlkDxe.h > +++ b/OvmfPkg/XenPvBlkDxe/XenPvBlkDxe.h > @@ -11,8 +11,9 @@ > #define __EFI_XEN_P

[edk2-devel] [PATCH 1/1] OvmfPkg/XenPvBlkDxe: Fix memory barrier macro

2022-07-19 Thread Anthony PERARD via groups.io
From: Anthony PERARD The macro "xen_mb()" needs to be a full memory barrier, that is it needs to also prevent stores from been reorder after loads which an x86 CPU can do (as I understand from reading [1]). So this patch makes use of "mfence" instruction. Currently, there's a good chance that Ov