Re: [PATCH 2/3] x86/entry: Make #PF/NMI/INT0x82 more amenable to livepatching

2024-01-24 Thread Roger Pau Monné
On Tue, Jan 23, 2024 at 02:43:15PM +0100, Jan Beulich wrote: > On 23.01.2024 14:37, Roger Pau Monné wrote: > > On Tue, Jan 23, 2024 at 10:22:10AM +0100, Jan Beulich wrote: > >> On 22.01.2024 19:17, Andrew Cooper wrote: > >>> It is bad form to have inter-function fallthrough. It only functions >

Re: [PATCH 2/3] x86/entry: Make #PF/NMI/INT0x82 more amenable to livepatching

2024-01-23 Thread Jan Beulich
On 23.01.2024 14:37, Roger Pau Monné wrote: > On Tue, Jan 23, 2024 at 10:22:10AM +0100, Jan Beulich wrote: >> On 22.01.2024 19:17, Andrew Cooper wrote: >>> It is bad form to have inter-function fallthrough. It only functions right >>> now because alignment padding bytes are NOPs. >> >> But that's

Re: [PATCH 2/3] x86/entry: Make #PF/NMI/INT0x82 more amenable to livepatching

2024-01-23 Thread Roger Pau Monné
On Tue, Jan 23, 2024 at 10:22:10AM +0100, Jan Beulich wrote: > On 22.01.2024 19:17, Andrew Cooper wrote: > > It is bad form to have inter-function fallthrough. It only functions right > > now because alignment padding bytes are NOPs. > > But that's a requirement anyway in executable sections.

Re: [PATCH 2/3] x86/entry: Make #PF/NMI/INT0x82 more amenable to livepatching

2024-01-23 Thread Jan Beulich
On 22.01.2024 19:17, Andrew Cooper wrote: > It is bad form to have inter-function fallthrough. It only functions right > now because alignment padding bytes are NOPs. But that's a requirement anyway in executable sections. > --- a/xen/arch/x86/x86_64/compat/entry.S > +++

[PATCH 2/3] x86/entry: Make #PF/NMI/INT0x82 more amenable to livepatching

2024-01-22 Thread Andrew Cooper
It is bad form to have inter-function fallthrough. It only functions right now because alignment padding bytes are NOPs. However, it also interferes with livepatching binary diffs, because the implicit grouping of the two functions isn't expressed in the ELF metadata. Signed-off-by: Andrew