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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 4/5] x86: use PDEP/PEXT for PFN/PDX conversion when available
I'm sorry for the bogus "Re:" in the original subject; not sure how that
happened.
Jan
>>> On 28.02.18 at 14:58, <JBeulich@xxxxxxxx> wrote:
> Both replace 6 instructions by a single one, further reducing code size,
> cache, and TLB footprint (in particular on systems supporting BMI2).
>
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
>
> --- a/xen/arch/x86/mm.c
> +++ b/xen/arch/x86/mm.c
> @@ -394,6 +394,7 @@ void __init arch_init_memory(void)
> const intpte_t pte_flags_mask = ~(PADDR_MASK & PAGE_MASK);
>
> paddr_t __read_mostly ma_real_mask = ~0UL;
> +unsigned long __read_mostly pfn_real_mask = ~0UL;
>
> #ifndef HAVE_GAS_QUOTED_EXPR_SYM
> intpte_t put_pte_flags_v(unsigned int flags)
> @@ -413,6 +414,17 @@ unsigned long ma2do(paddr_t ma)
> return (ma & ma_va_bottom_mask) |
> ((ma & ma_top_mask) >> pfn_pdx_hole_shift);
> }
> +
> +/* Conversion between PDX and PFN. */
> +unsigned long pdx2pfn(unsigned long pdx)
> +{
> + return generic_pdx_to_pfn(pdx);
> +}
> +
> +unsigned long pfn2pdx(unsigned long pfn)
> +{
> + return generic_pfn_to_pdx(pfn);
> +}
> #endif
>
> int page_is_ram_type(unsigned long mfn, unsigned long mem_type)
> --- a/xen/arch/x86/srat.c
> +++ b/xen/arch/x86/srat.c
> @@ -448,6 +448,7 @@ void __init srat_parse_regions(u64 addr)
> pfn_pdx_hole_setup(mask >> PAGE_SHIFT);
>
> ma_real_mask = ma_top_mask | ma_va_bottom_mask;
> + pfn_real_mask = pfn_top_mask | pfn_pdx_bottom_mask;
> }
>
> /* Use the information discovered above to actually set up the nodes. */
> --- /dev/null
> +++ b/xen/include/asm-arm/pdx.h
> @@ -0,0 +1,16 @@
> +#ifndef __ASM_ARM_PDX_H__
> +#define __ASM_ARM_PDX_H__
> +
> +#define pdx_to_pfn generic_pdx_to_pfn
> +#define pfn_to_pdx generic_pfn_to_pdx
> +
> +#endif /* __ASM_ARM_PDX_H__ */
> +
> +/*
> + * Local variables:
> + * mode: C
> + * c-file-style: "BSD"
> + * c-basic-offset: 4
> + * indent-tabs-mode: nil
> + * End:
> + */
> --- /dev/null
> +++ b/xen/include/asm-x86/pdx.h
> @@ -0,0 +1,97 @@
> +#ifndef __ASM_ARM_PDX_H__
> +#define __ASM_ARM_PDX_H__
> +
> +#include <asm/alternative.h>
> +#include <asm/asm_defns.h>
> +#include <asm/cpufeature.h>
> +
> +extern unsigned long pfn_real_mask;
> +
> +static always_inline unsigned long pdx_to_pfn(unsigned long pdx)
> +{
> + unsigned long pfn;
> +
> +#ifdef HAVE_GAS_QUOTED_EXPR_SYM
> +#define SYMNAME(pfx...) "\"" #pfx "pdx2pfn_%[pfn]_%[pdx]\""
> + alternative_io_2("call " SYMNAME() "; " ASM_NOP4 "\t"
> + LINKONCE_PROLOGUE(SYMNAME)
> + "mov %[shift], %%ecx\n\t"
> + "mov %[pdx], %[pfn]\n\t"
> + "and %[bmask], %[pfn]\n\t"
> + "shl %%cl, %[pdx]\n\t"
> + "and %[tmask], %[pdx]\n\t"
> + "or %[pdx], %[pfn]\n\t"
> + "ret\n\t"
> + LINKONCE_EPILOGUE(SYMNAME),
> + "call " SYMNAME(), X86_FEATURE_ALWAYS,
> + "pdep %[mask], %[pdx], %[pfn]", X86_FEATURE_BMI2,
> + ASM_OUTPUT2([pfn] "=&r" (pfn), [pdx] "+r" (pdx)),
> + [mask] "m" (pfn_real_mask),
> + [shift] "m" (pfn_pdx_hole_shift),
> + [bmask] "m" (pfn_pdx_bottom_mask),
> + [tmask] "m" (pfn_top_mask)
> + : "ecx");
> +#undef SYMNAME
> +#else
> + alternative_io_2("call pdx2pfn; " ASM_NOP4,
> + "call pdx2pfn", X86_FEATURE_ALWAYS,
> + /* pdep pfn_real_mask(%rip), %rdi, %rax */
> + ".byte 0xc4, 0xe2, 0xc3, 0xf5, 0x05\n\t"
> + ".long pfn_real_mask - 4 - .",
> + X86_FEATURE_BMI2,
> + ASM_OUTPUT2("=a" (pfn), "+D" (pdx)), "m"
> (pfn_real_mask)
> + : "rcx", "rdx", "rsi", "r8", "r9", "r10", "r11");
> +#endif
> +
> + return pfn;
> +}
> +
> +static always_inline unsigned long pfn_to_pdx(unsigned long pfn)
> +{
> + unsigned long pdx;
> +
> +#ifdef HAVE_GAS_QUOTED_EXPR_SYM
> +#define SYMNAME(pfx...) "\"" #pfx "pfn2pdx_%[pdx]_%[pfn]\""
> + alternative_io_2("call " SYMNAME() "; " ASM_NOP4 "\t"
> + LINKONCE_PROLOGUE(SYMNAME)
> + "mov %[tmask], %[pdx]\n\t"
> + "mov %[shift], %%ecx\n\t"
> + "and %[pfn], %[pdx]\n\t"
> + "and %[bmask], %[pfn]\n\t"
> + "shr %%cl, %[pdx]\n\t"
> + "or %[pfn], %[pdx]\n\t"
> + "ret\n\t"
> + LINKONCE_EPILOGUE(SYMNAME),
> + "call " SYMNAME(), X86_FEATURE_ALWAYS,
> + "pext %[mask], %[pfn], %[pdx]", X86_FEATURE_BMI2,
> + ASM_OUTPUT2([pdx] "=&r" (pdx), [pfn] "+r" (pfn)),
> + [mask] "m" (pfn_real_mask),
> + [shift] "m" (pfn_pdx_hole_shift),
> + [bmask] "m" (pfn_pdx_bottom_mask),
> + [tmask] "m" (pfn_top_mask)
> + : "ecx");
> +#undef SYMNAME
> +#else
> + alternative_io_2("call pfn2pdx; " ASM_NOP4,
> + "call pfn2pdx", X86_FEATURE_ALWAYS,
> + /* pext pfn_real_mask(%rip), %rdi, %rax */
> + ".byte 0xc4, 0xe2, 0xc2, 0xf5, 0x05\n\t"
> + ".long pfn_real_mask - 4 - .",
> + X86_FEATURE_BMI2,
> + ASM_OUTPUT2("=a" (pdx), "+D" (pfn)), "m"
> (pfn_real_mask)
> + : "rcx", "rdx", "rsi", "r8", "r9", "r10", "r11");
> +#endif
> +
> + return pdx;
> +}
> +
> +#endif /* __ASM_ARM_PDX_H__ */
> +
> +/*
> + * Local variables:
> + * mode: C
> + * c-file-style: "BSD"
> + * c-basic-offset: 4
> + * indent-tabs-mode: nil
> + * End:
> + */
> --- a/xen/include/xen/pdx.h
> +++ b/xen/include/xen/pdx.h
> @@ -23,13 +23,13 @@ extern void set_pdx_range(unsigned long
>
> bool __mfn_valid(unsigned long mfn);
>
> -static inline unsigned long pfn_to_pdx(unsigned long pfn)
> +static inline unsigned long generic_pfn_to_pdx(unsigned long pfn)
> {
> return (pfn & pfn_pdx_bottom_mask) |
> ((pfn & pfn_top_mask) >> pfn_pdx_hole_shift);
> }
>
> -static inline unsigned long pdx_to_pfn(unsigned long pdx)
> +static inline unsigned long generic_pdx_to_pfn(unsigned long pdx)
> {
> return (pdx & pfn_pdx_bottom_mask) |
> ((pdx << pfn_pdx_hole_shift) & pfn_top_mask);
> @@ -37,6 +37,8 @@ static inline unsigned long pdx_to_pfn(u
>
> extern void pfn_pdx_hole_setup(unsigned long);
>
> +#include <asm/pdx.h>
> +
> #endif /* HAS_PDX */
> #endif /* __XEN_PDX_H__ */
>
>
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxxxxxxxxx
> https://lists.xenproject.org/mailman/listinfo/xen-devel
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