On 16.07.2025 15:28, Andrew Cooper wrote:
> Intel have run out of model space in Family 6 and will start using Family 19
> starting with Diamond Rapids. Xen, like Linux, has model checking logic which
> will malfunction owing to bad assumptions about the family field.
>
> Reorder the family, vendor and model fields so they can be accessed together
> as a single vfm field.
>
> As we're cleaning up the logic, take the opportunity to introduce better
> names, dropping the x86 prefix.
>
> No functional change.
>
> Signed-off-by: Andrew Cooper <andrew.coop...@citrix.com>
In principle
Reviewed-by: Jan Beulich <jbeul...@suse.com>
Two remarks, though:
> --- a/xen/arch/x86/include/asm/cpufeature.h
> +++ b/xen/arch/x86/include/asm/cpufeature.h
> @@ -20,10 +20,30 @@
> #ifndef __ASSEMBLY__
>
> struct cpuinfo_x86 {
> - unsigned char x86; /* CPU family */
> - unsigned char x86_vendor; /* CPU vendor */
> - unsigned char x86_model;
> - unsigned char x86_mask;
> + /* TODO: Phase out the x86 prefixed names. */
> + union {
> + struct {
> + union {
> + uint8_t x86_model;
> + uint8_t model;
> + };
> + union {
> + uint8_t x86;
> + uint8_t family;
> + };
> + union {
> + uint8_t x86_vendor;
> + uint8_t vendor;
> + };
> + uint8_t _rsvd;
Can we perhaps name this e.g. _zero, so it's clear that it cannot be
repurposed?
> --- a/xen/arch/x86/setup.c
> +++ b/xen/arch/x86/setup.c
> @@ -178,7 +178,9 @@ void *stack_start = cpu0_stack + STACK_SIZE -
> sizeof(struct cpu_info);
> /* Used by the boot asm and EFI to stash the multiboot_info paddr. */
> unsigned int __initdata multiboot_ptr;
>
> -struct cpuinfo_x86 __read_mostly boot_cpu_data = { 0, 0, 0, 0, -1 };
> +struct cpuinfo_x86 __read_mostly boot_cpu_data = {
> + .cpuid_level = -1,
> +};
So you retain the bogus setting of this field. Would you mind taking a
look at [1], one of the many things that I never heard back on? I'm
deliberately purging that non-sense there as a (side-)effect. Plus
really I'm getting tired of having to re-base my long-pending changes
over ones you are helped getting in pretty quickly. No matter that this
one's going to be one of the easy ones (I hope).
Jan
[1] https://lists.xen.org/archives/html/xen-devel/2024-02/msg00726.html
