[PATCH] Partial revert of "x86/MCE: optional build of AMD/Intel MCE code"

[PATCH] Partial revert of "x86/MCE: optional build of AMD/Intel MCE code"

[Andrew Cooper]

{cmci,lmce}_support are written during S3 resume, so cannot live in
__ro_after_init.  Move them back to being __read_mostly, as they were
originally.

Link: https://gitlab.com/xen-project/xen/-/jobs/6966698361
Fixes: 19b6e9f9149f ("x86/MCE: optional build of AMD/Intel MCE code")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Jan Beulich <JBeulich@suse.com>
CC: Roger Pau Monné <roger.pau@citrix.com>
CC: Sergiy Kibrik <Sergiy_Kibrik@epam.com>
CC: Stefano Stabellini <sstabellini@kernel.org>
CC: Oleksii Kurochko <oleksii.kurochko@gmail.com>

We're past feature freeze and this was a silent change in a patch, which was
also untested.  A 30s look at mcheck_init() shows clearly that it's not a 30s
job to fix.
---
 xen/arch/x86/cpu/mcheck/mce.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/xen/arch/x86/cpu/mcheck/mce.c b/xen/arch/x86/cpu/mcheck/mce.c
index 1664ca6412ac..32c1b2756b90 100644
--- a/xen/arch/x86/cpu/mcheck/mce.c
+++ b/xen/arch/x86/cpu/mcheck/mce.c
@@ -38,10 +38,10 @@ DEFINE_PER_CPU_READ_MOSTLY(unsigned int, nr_mce_banks);
 unsigned int __read_mostly firstbank;
 unsigned int __read_mostly ppin_msr;
 uint8_t __read_mostly cmci_apic_vector;
-bool __ro_after_init cmci_support;
+bool __read_mostly cmci_support;
 
 /* If mce_force_broadcast == 1, lmce_support will be disabled forcibly. */
-bool __ro_after_init lmce_support;
+bool __read_mostly lmce_support;
 
 DEFINE_PER_CPU_READ_MOSTLY(struct mca_banks *, poll_bankmask);
 DEFINE_PER_CPU_READ_MOSTLY(struct mca_banks *, no_cmci_banks);

base-commit: 0840bc5ea114f536a4bdfb2ca095b79f2069aae6
-- 
2.30.2

Re: [PATCH] Partial revert of "x86/MCE: optional build of AMD/Intel MCE code"

[Jan Beulich]

On 29.05.2024 12:37, Andrew Cooper wrote:
> {cmci,lmce}_support are written during S3 resume, so cannot live in
> __ro_after_init.  Move them back to being __read_mostly, as they were
> originally.
> 
> Link: https://gitlab.com/xen-project/xen/-/jobs/6966698361
> Fixes: 19b6e9f9149f ("x86/MCE: optional build of AMD/Intel MCE code")
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>

Acked-by: Jan Beulich <jbeulich@suse.com>

Re: [PATCH] Partial revert of "x86/MCE: optional build of AMD/Intel MCE code"

[Oleksii K.]

On Wed, 2024-05-29 at 11:37 +0100, Andrew Cooper wrote:
> {cmci,lmce}_support are written during S3 resume, so cannot live in
> __ro_after_init.  Move them back to being __read_mostly, as they were
> originally.
> 
> Link: https://gitlab.com/xen-project/xen/-/jobs/6966698361
> Fixes: 19b6e9f9149f ("x86/MCE: optional build of AMD/Intel MCE code")
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
> ---
> CC: Jan Beulich <JBeulich@suse.com>
> CC: Roger Pau Monné <roger.pau@citrix.com>
> CC: Sergiy Kibrik <Sergiy_Kibrik@epam.com>
> CC: Stefano Stabellini <sstabellini@kernel.org>
> CC: Oleksii Kurochko <oleksii.kurochko@gmail.com>
> 
> We're past feature freeze and this was a silent change in a patch,
> which was
> also untested.  A 30s look at mcheck_init() shows clearly that it's
> not a 30s
> job to fix.
> ---
Release-Acked-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>

~ Oleksii
>  xen/arch/x86/cpu/mcheck/mce.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/xen/arch/x86/cpu/mcheck/mce.c
> b/xen/arch/x86/cpu/mcheck/mce.c
> index 1664ca6412ac..32c1b2756b90 100644
> --- a/xen/arch/x86/cpu/mcheck/mce.c
> +++ b/xen/arch/x86/cpu/mcheck/mce.c
> @@ -38,10 +38,10 @@ DEFINE_PER_CPU_READ_MOSTLY(unsigned int,
> nr_mce_banks);
>  unsigned int __read_mostly firstbank;
>  unsigned int __read_mostly ppin_msr;
>  uint8_t __read_mostly cmci_apic_vector;
> -bool __ro_after_init cmci_support;
> +bool __read_mostly cmci_support;
>  
>  /* If mce_force_broadcast == 1, lmce_support will be disabled
> forcibly. */
> -bool __ro_after_init lmce_support;
> +bool __read_mostly lmce_support;
>  
>  DEFINE_PER_CPU_READ_MOSTLY(struct mca_banks *, poll_bankmask);
>  DEFINE_PER_CPU_READ_MOSTLY(struct mca_banks *, no_cmci_banks);
> 
> base-commit: 0840bc5ea114f536a4bdfb2ca095b79f2069aae6