| Message ID | 20241009150855.804605-8-richard.henderson@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | accel/tcg: Convert victim tlb to IntervalTree | expand |
On 10/9/24 08:08, Richard Henderson wrote: > We expect masked address spaces to be quite large, e.g. 56 bits > for AArch64 top-byte-ignore mode. We do not expect addr+len to > wrap around, but it is possible with AArch64 guest flush range > instructions. > > Convert this unlikely case to a full tlb flush. This can simplify > the subroutines actually performing the range flush. > > Signed-off-by: Richard Henderson <richard.henderson@linaro.org> > --- > accel/tcg/cputlb.c | 16 ++++++++++++---- > 1 file changed, 12 insertions(+), 4 deletions(-) > > diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c > index 93b42d18ee..8affa25db3 100644 > --- a/accel/tcg/cputlb.c > +++ b/accel/tcg/cputlb.c > @@ -808,8 +808,12 @@ void tlb_flush_range_by_mmuidx(CPUState *cpu, vaddr addr, > tlb_flush_page_by_mmuidx(cpu, addr, idxmap); > return; > } > - /* If no page bits are significant, this devolves to tlb_flush. */ > - if (bits < TARGET_PAGE_BITS) { > + /* > + * If no page bits are significant, this devolves to full flush. > + * If addr+len wraps in len bits, fall back to full flush. > + */ > + if (bits < TARGET_PAGE_BITS > + || (bits < TARGET_LONG_BITS && (addr ^ (addr + len - 1)) >> bits)) { > tlb_flush_by_mmuidx(cpu, idxmap); > return; > } > @@ -849,8 +853,12 @@ void tlb_flush_range_by_mmuidx_all_cpus_synced(CPUState *src_cpu, > tlb_flush_page_by_mmuidx_all_cpus_synced(src_cpu, addr, idxmap); > return; > } > - /* If no page bits are significant, this devolves to tlb_flush. */ > - if (bits < TARGET_PAGE_BITS) { > + /* > + * If no page bits are significant, this devolves to full flush. > + * If addr+len wraps in len bits, fall back to full flush. > + */ > + if (bits < TARGET_PAGE_BITS > + || (bits < TARGET_LONG_BITS && (addr ^ (addr + len - 1)) >> bits)) { > tlb_flush_by_mmuidx_all_cpus_synced(src_cpu, idxmap); > return; > } Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c index 93b42d18ee..8affa25db3 100644 --- a/accel/tcg/cputlb.c +++ b/accel/tcg/cputlb.c @@ -808,8 +808,12 @@ void tlb_flush_range_by_mmuidx(CPUState *cpu, vaddr addr, tlb_flush_page_by_mmuidx(cpu, addr, idxmap); return; } - /* If no page bits are significant, this devolves to tlb_flush. */ - if (bits < TARGET_PAGE_BITS) { + /* + * If no page bits are significant, this devolves to full flush. + * If addr+len wraps in len bits, fall back to full flush. + */ + if (bits < TARGET_PAGE_BITS + || (bits < TARGET_LONG_BITS && (addr ^ (addr + len - 1)) >> bits)) { tlb_flush_by_mmuidx(cpu, idxmap); return; } @@ -849,8 +853,12 @@ void tlb_flush_range_by_mmuidx_all_cpus_synced(CPUState *src_cpu, tlb_flush_page_by_mmuidx_all_cpus_synced(src_cpu, addr, idxmap); return; } - /* If no page bits are significant, this devolves to tlb_flush. */ - if (bits < TARGET_PAGE_BITS) { + /* + * If no page bits are significant, this devolves to full flush. + * If addr+len wraps in len bits, fall back to full flush. + */ + if (bits < TARGET_PAGE_BITS + || (bits < TARGET_LONG_BITS && (addr ^ (addr + len - 1)) >> bits)) { tlb_flush_by_mmuidx_all_cpus_synced(src_cpu, idxmap); return; }
We expect masked address spaces to be quite large, e.g. 56 bits for AArch64 top-byte-ignore mode. We do not expect addr+len to wrap around, but it is possible with AArch64 guest flush range instructions. Convert this unlikely case to a full tlb flush. This can simplify the subroutines actually performing the range flush. Signed-off-by: Richard Henderson <richard.henderson@linaro.org> --- accel/tcg/cputlb.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-)