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Diffstat (limited to 'accel/tcg/tlb-bounds.h')
| -rw-r--r-- | accel/tcg/tlb-bounds.h | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/accel/tcg/tlb-bounds.h b/accel/tcg/tlb-bounds.h new file mode 100644 index 0000000..efd34d4 --- /dev/null +++ b/accel/tcg/tlb-bounds.h @@ -0,0 +1,32 @@ +/* + * softmmu size bounds + * SPDX-License-Identifier: LGPL-2.1-or-later + */ + +#ifndef ACCEL_TCG_TLB_BOUNDS_H +#define ACCEL_TCG_TLB_BOUNDS_H + +#define CPU_TLB_DYN_MIN_BITS 6 +#define CPU_TLB_DYN_DEFAULT_BITS 8 + +# if HOST_LONG_BITS == 32 +/* Make sure we do not require a double-word shift for the TLB load */ +# define CPU_TLB_DYN_MAX_BITS (32 - TARGET_PAGE_BITS) +# else /* HOST_LONG_BITS == 64 */ +/* + * Assuming TARGET_PAGE_BITS==12, with 2**22 entries we can cover 2**(22+12) == + * 2**34 == 16G of address space. This is roughly what one would expect a + * TLB to cover in a modern (as of 2018) x86_64 CPU. For instance, Intel + * Skylake's Level-2 STLB has 16 1G entries. + * Also, make sure we do not size the TLB past the guest's address space. + */ +# ifdef TARGET_PAGE_BITS_VARY +# define CPU_TLB_DYN_MAX_BITS \ + MIN(22, TARGET_VIRT_ADDR_SPACE_BITS - TARGET_PAGE_BITS) +# else +# define CPU_TLB_DYN_MAX_BITS \ + MIN_CONST(22, TARGET_VIRT_ADDR_SPACE_BITS - TARGET_PAGE_BITS) +# endif +# endif + +#endif /* ACCEL_TCG_TLB_BOUNDS_H */ |