On 12/30/24 11:53, Rik van Riel wrote:
> The CPU advertises the maximum number of pages that can be shot down
> with one INVLPGB instruction in the CPUID data.
>
> Save that information for later use.
>
> Signed-off-by: Rik van Riel <riel@xxxxxxxxxxx>
> ---
> arch/x86/include/asm/tlbflush.h | 1 +
> arch/x86/kernel/cpu/amd.c | 8 ++++++++
> arch/x86/kernel/setup.c | 4 ++++
> 3 files changed, 13 insertions(+)
>
> diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h
> index 02fc2aa06e9e..7d1468a3967b 100644
> --- a/arch/x86/include/asm/tlbflush.h
> +++ b/arch/x86/include/asm/tlbflush.h
> @@ -182,6 +182,7 @@ static inline void cr4_init_shadow(void)
>
> extern unsigned long mmu_cr4_features;
> extern u32 *trampoline_cr4_features;
> +extern u16 invlpgb_count_max;
>
> extern void initialize_tlbstate_and_flush(void);
>
> diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
> index 79d2e17f6582..226b8fc64bfc 100644
> --- a/arch/x86/kernel/cpu/amd.c
> +++ b/arch/x86/kernel/cpu/amd.c
> @@ -1135,6 +1135,14 @@ static void cpu_detect_tlb_amd(struct cpuinfo_x86 *c)
> tlb_lli_2m[ENTRIES] = eax & mask;
>
> tlb_lli_4m[ENTRIES] = tlb_lli_2m[ENTRIES] >> 1;
> +
> + if (c->extended_cpuid_level < 0x80000008)
> + return;
Can this just be based on cpu_feature_enabled(X86_FEATURE_TLBI), e.g:
if (cpu_feature_enabled(X86_FEATURE_TLBI))
invlpgb_count_max = (cpuid_edx(0x80000008) & 0xffff) + 1
Then you can squash this and the previous patch.
Thanks,
Tom
> +
> + cpuid(0x80000008, &eax, &ebx, &ecx, &edx);
> +
> + /* Max number of pages INVLPGB can invalidate in one shot */
> + invlpgb_count_max = (edx & 0xffff) + 1;
> }
>
> static const struct cpu_dev amd_cpu_dev = {
> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> index f1fea506e20f..6c4d08f8f7b1 100644
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -138,6 +138,10 @@ __visible unsigned long mmu_cr4_features __ro_after_init;
> __visible unsigned long mmu_cr4_features __ro_after_init = X86_CR4_PAE;
> #endif
>
> +#ifdef CONFIG_CPU_SUP_AMD
> +u16 invlpgb_count_max __ro_after_init;
> +#endif
> +
> #ifdef CONFIG_IMA
> static phys_addr_t ima_kexec_buffer_phys;
> static size_t ima_kexec_buffer_size;
