diff mbox series

[08/15] accel/tcg: Simplify CPU_TLB_DYN_MAX_BITS

Message ID 20250424011918.599958-9-richard.henderson@linaro.org
State New
Headers show
Series accel/tcg: Compile tb-maint.c twice | expand

Commit Message

Richard Henderson April 24, 2025, 1:19 a.m. UTC 
Stop taking TARGET_VIRT_ADDR_SPACE_BITS into account.

Since we currently bound CPU_TLB_DYN_MAX_BITS to 22,
the new bound with a 4k page size is 20, which isn't
so different.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 accel/tcg/tlb-bounds.h | 21 +--------------------
 1 file changed, 1 insertion(+), 20 deletions(-)

Comments

Pierrick Bouvier April 25, 2025, 7:41 p.m. UTC | #1 
On 4/23/25 18:19, Richard Henderson wrote:
> Stop taking TARGET_VIRT_ADDR_SPACE_BITS into account.
> 
> Since we currently bound CPU_TLB_DYN_MAX_BITS to 22,
> the new bound with a 4k page size is 20, which isn't
> so different.
> 
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>   accel/tcg/tlb-bounds.h | 21 +--------------------
>   1 file changed, 1 insertion(+), 20 deletions(-)

Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
diff mbox series

Patch

diff --git a/accel/tcg/tlb-bounds.h b/accel/tcg/tlb-bounds.h
index efd34d4793..f83d9ac9ee 100644
--- a/accel/tcg/tlb-bounds.h
+++ b/accel/tcg/tlb-bounds.h
@@ -7,26 +7,7 @@ 
 #define ACCEL_TCG_TLB_BOUNDS_H
 
 #define CPU_TLB_DYN_MIN_BITS 6
+#define CPU_TLB_DYN_MAX_BITS (32 - TARGET_PAGE_BITS)
 #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 */