Re: [PATCH v2 2/8] x86: Add AMX XTILECFG and XTILEDATA components

[David Edmondson <david.edmondson@oracle.com>]

On Wednesday, 2022-02-16 at 22:04:28 -08, Yang Zhong wrote:

> From: Jing Liu <jing2.liu@intel.com>
>
> The AMX TILECFG register and the TMMx tile data registers are
> saved/restored via XSAVE, respectively in state component 17
> (64 bytes) and state component 18 (8192 bytes).
>
> Add AMX feature bits to x86_ext_save_areas array to set
> up AMX components. Add structs that define the layout of
> AMX XSAVE areas and use QEMU_BUILD_BUG_ON to validate the
> structs sizes.
>
> Signed-off-by: Jing Liu <jing2.liu@intel.com>
> Signed-off-by: Yang Zhong <yang.zhong@intel.com>

Reviewed-by: David Edmondson <david.edmondson@oracle.com>

> ---
>  target/i386/cpu.h | 18 +++++++++++++++++-
>  target/i386/cpu.c |  8 ++++++++
>  2 files changed, 25 insertions(+), 1 deletion(-)
>
> diff --git a/target/i386/cpu.h b/target/i386/cpu.h
> index de1dc124ab..06d2d6bccf 100644
> --- a/target/i386/cpu.h
> +++ b/target/i386/cpu.h
> @@ -537,6 +537,8 @@ typedef enum X86Seg {
>  #define XSTATE_ZMM_Hi256_BIT            6
>  #define XSTATE_Hi16_ZMM_BIT             7
>  #define XSTATE_PKRU_BIT                 9
> +#define XSTATE_XTILE_CFG_BIT            17
> +#define XSTATE_XTILE_DATA_BIT           18
>
>  #define XSTATE_FP_MASK                  (1ULL << XSTATE_FP_BIT)
>  #define XSTATE_SSE_MASK                 (1ULL << XSTATE_SSE_BIT)
> @@ -845,6 +847,8 @@ typedef uint64_t FeatureWordArray[FEATURE_WORDS];
>  #define CPUID_7_0_EDX_TSX_LDTRK         (1U << 16)
>  /* AVX512_FP16 instruction */
>  #define CPUID_7_0_EDX_AVX512_FP16       (1U << 23)
> +/* AMX tile (two-dimensional register) */
> +#define CPUID_7_0_EDX_AMX_TILE          (1U << 24)
>  /* Speculation Control */
>  #define CPUID_7_0_EDX_SPEC_CTRL         (1U << 26)
>  /* Single Thread Indirect Branch Predictors */
> @@ -1348,6 +1352,16 @@ typedef struct XSavePKRU {
>      uint32_t padding;
>  } XSavePKRU;
>
> +/* Ext. save area 17: AMX XTILECFG state */
> +typedef struct XSaveXTILECFG {
> +    uint8_t xtilecfg[64];
> +} XSaveXTILECFG;
> +
> +/* Ext. save area 18: AMX XTILEDATA state */
> +typedef struct XSaveXTILEDATA {
> +    uint8_t xtiledata[8][1024];
> +} XSaveXTILEDATA;
> +
>  QEMU_BUILD_BUG_ON(sizeof(XSaveAVX) != 0x100);
>  QEMU_BUILD_BUG_ON(sizeof(XSaveBNDREG) != 0x40);
>  QEMU_BUILD_BUG_ON(sizeof(XSaveBNDCSR) != 0x40);
> @@ -1355,6 +1369,8 @@ QEMU_BUILD_BUG_ON(sizeof(XSaveOpmask) != 0x40);
>  QEMU_BUILD_BUG_ON(sizeof(XSaveZMM_Hi256) != 0x200);
>  QEMU_BUILD_BUG_ON(sizeof(XSaveHi16_ZMM) != 0x400);
>  QEMU_BUILD_BUG_ON(sizeof(XSavePKRU) != 0x8);
> +QEMU_BUILD_BUG_ON(sizeof(XSaveXTILECFG) != 0x40);
> +QEMU_BUILD_BUG_ON(sizeof(XSaveXTILEDATA) != 0x2000);
>
>  typedef struct ExtSaveArea {
>      uint32_t feature, bits;
> @@ -1362,7 +1378,7 @@ typedef struct ExtSaveArea {
>      uint32_t ecx;
>  } ExtSaveArea;
>
> -#define XSAVE_STATE_AREA_COUNT (XSTATE_PKRU_BIT + 1)
> +#define XSAVE_STATE_AREA_COUNT (XSTATE_XTILE_DATA_BIT + 1)
>
>  extern ExtSaveArea x86_ext_save_areas[XSAVE_STATE_AREA_COUNT];
>
> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> index 37f06b0b1a..ea7e8f9081 100644
> --- a/target/i386/cpu.c
> +++ b/target/i386/cpu.c
> @@ -1401,6 +1401,14 @@ ExtSaveArea x86_ext_save_areas[XSAVE_STATE_AREA_COUNT] = {
>      [XSTATE_PKRU_BIT] =
>            { .feature = FEAT_7_0_ECX, .bits = CPUID_7_0_ECX_PKU,
>              .size = sizeof(XSavePKRU) },
> +    [XSTATE_XTILE_CFG_BIT] = {
> +        .feature = FEAT_7_0_EDX, .bits = CPUID_7_0_EDX_AMX_TILE,
> +        .size = sizeof(XSaveXTILECFG),
> +    },
> +    [XSTATE_XTILE_DATA_BIT] = {
> +        .feature = FEAT_7_0_EDX, .bits = CPUID_7_0_EDX_AMX_TILE,
> +        .size = sizeof(XSaveXTILEDATA)
> +    },
>  };
>
>  static uint32_t xsave_area_size(uint64_t mask)

dme.
-- 
Would you offer your throat to the wolf with the red roses?