From dff1ab68d8c5d4703e07018f504fce6944c529a4 Mon Sep 17 00:00:00 2001 From: LIU Zhiwei Date: Fri, 1 Sep 2023 14:01:18 +0800 Subject: [PATCH] accel/tcg: Fix the comment for CPUTLBEntryFull When memory region is ram, the lower TARGET_PAGE_BITS is not the physical section number. Instead, its value is always 0. Add comment and assert to make it clear. Signed-off-by: LIU Zhiwei Message-Id: <20230901060118.379-1-zhiwei_liu@linux.alibaba.com> Reviewed-by: Richard Henderson Signed-off-by: Richard Henderson --- accel/tcg/cputlb.c | 11 +++++++---- include/exec/cpu-defs.h | 12 ++++++------ 2 files changed, 13 insertions(+), 10 deletions(-) diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c index c643d66190..03e27b2a38 100644 --- a/accel/tcg/cputlb.c +++ b/accel/tcg/cputlb.c @@ -1193,6 +1193,7 @@ void tlb_set_page_full(CPUState *cpu, int mmu_idx, write_flags = read_flags; if (is_ram) { iotlb = memory_region_get_ram_addr(section->mr) + xlat; + assert(!(iotlb & ~TARGET_PAGE_MASK)); /* * Computing is_clean is expensive; avoid all that unless * the page is actually writable. @@ -1255,10 +1256,12 @@ void tlb_set_page_full(CPUState *cpu, int mmu_idx, /* refill the tlb */ /* - * At this point iotlb contains a physical section number in the lower - * TARGET_PAGE_BITS, and either - * + the ram_addr_t of the page base of the target RAM (RAM) - * + the offset within section->mr of the page base (I/O, ROMD) + * When memory region is ram, iotlb contains a TARGET_PAGE_BITS + * aligned ram_addr_t of the page base of the target RAM. + * Otherwise, iotlb contains + * - a physical section number in the lower TARGET_PAGE_BITS + * - the offset within section->mr of the page base (I/O, ROMD) with the + * TARGET_PAGE_BITS masked off. * We subtract addr_page (which is page aligned and thus won't * disturb the low bits) to give an offset which can be added to the * (non-page-aligned) vaddr of the eventual memory access to get diff --git a/include/exec/cpu-defs.h b/include/exec/cpu-defs.h index fb4c8d480f..350287852e 100644 --- a/include/exec/cpu-defs.h +++ b/include/exec/cpu-defs.h @@ -100,12 +100,12 @@ typedef struct CPUTLBEntryFull { /* * @xlat_section contains: - * - in the lower TARGET_PAGE_BITS, a physical section number - * - with the lower TARGET_PAGE_BITS masked off, an offset which - * must be added to the virtual address to obtain: - * + the ram_addr_t of the target RAM (if the physical section - * number is PHYS_SECTION_NOTDIRTY or PHYS_SECTION_ROM) - * + the offset within the target MemoryRegion (otherwise) + * - For ram, an offset which must be added to the virtual address + * to obtain the ram_addr_t of the target RAM + * - For other memory regions, + * + in the lower TARGET_PAGE_BITS, the physical section number + * + with the TARGET_PAGE_BITS masked off, the offset within + * the target MemoryRegion */ hwaddr xlat_section; -- 2.11.0