Re: [PATCH] x86/entry: fix entry_INT80_compat for Xen PV guests

[Jan Beulich]

On 16.08.2022 09:11, Juergen Gross wrote:
> Commit c89191ce67ef ("x86/entry: Convert SWAPGS to swapgs and remove
> the definition of SWAPGS") missed one use case of SWAPGS in
> entry_INT80_compat. Removing of the SWAPGS macro led to asm just
> using "swapgs", as it is accepting instructions in capital letters,
> too.
> 
> This in turn leads to splats in Xen PV guests like:
> 
> [   36.145223] general protection fault, maybe for address 0x2d: 0000 [#1] PREEMPT SMP NOPTI
> [   36.145794] CPU: 2 PID: 1847 Comm: ld-linux.so.2 Not tainted 5.19.1-1-default #1 openSUSE Tumbleweed f3b44bfb672cdb9f235aff53b57724eba8b9411b
> [   36.146608] Hardware name: HP ProLiant ML350p Gen8, BIOS P72 11/14/2013
> [   36.148126] RIP: e030:entry_INT80_compat+0x3/0xa3
> 
> Fix that by open coding this single instance of the SWAPGS macro.
> 
> Cc: <stable@xxxxxxxxxxxxxxx> # 5.19
> Fixes: c89191ce67ef ("x86/entry: Convert SWAPGS to swapgs and remove the definition of SWAPGS")
> Signed-off-by: Juergen Gross <jgross@xxxxxxxx>

Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>