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accel/tcg: Avoid caching overwritten tlb entries 

When installing a TLB entry, remove any cached version of the
same page in the VTLB.  If the existing TLB entry matches, do
not copy into the VTLB, but overwrite it.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2018-06-29 13:07:08 -07:00
parent 4b1a3e1e34
commit 68fea03855
1 changed files with 36 additions and 27 deletions
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63
accel/tcg/cputlb.c
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@ -235,17 +235,30 @@ void tlb_flush_by_mmuidx_all_cpus_synced(CPUState *src_cpu,
async_safe_run_on_cpu(src_cpu, fn, RUN_ON_CPU_HOST_INT(idxmap));
}
static inline void tlb_flush_entry(CPUTLBEntry *tlb_entry, target_ulong addr)
static inline bool tlb_hit_page_anyprot(CPUTLBEntry *tlb_entry,
target_ulong page)
{
if (tlb_hit_page(tlb_entry->addr_read, addr) ||
tlb_hit_page(tlb_entry->addr_write, addr) ||
tlb_hit_page(tlb_entry->addr_code, addr)) {
return tlb_hit_page(tlb_entry->addr_read, page) ||
tlb_hit_page(tlb_entry->addr_write, page) ||
tlb_hit_page(tlb_entry->addr_code, page);
}
static inline void tlb_flush_entry(CPUTLBEntry *tlb_entry, target_ulong page)
{
if (tlb_hit_page_anyprot(tlb_entry, page)) {
memset(tlb_entry, -1, sizeof(*tlb_entry));
}
}
static inline void tlb_flush_vtlb_page(CPUArchState *env, int mmu_idx,
target_ulong page)
{
int k;
for (k = 0; k < CPU_VTLB_SIZE; k++) {
tlb_flush_entry(&env->tlb_v_table[mmu_idx][k], page);
}
}
static void tlb_flush_page_async_work(CPUState *cpu, run_on_cpu_data data)
{
CPUArchState *env = cpu->env_ptr;
@ -271,14 +284,7 @@ static void tlb_flush_page_async_work(CPUState *cpu, run_on_cpu_data data)
i = (addr >> TARGET_PAGE_BITS) & (CPU_TLB_SIZE - 1);
for (mmu_idx = 0; mmu_idx < NB_MMU_MODES; mmu_idx++) {
tlb_flush_entry(&env->tlb_table[mmu_idx][i], addr);
}
/* check whether there are entries that need to be flushed in the vtlb */
for (mmu_idx = 0; mmu_idx < NB_MMU_MODES; mmu_idx++) {
int k;
for (k = 0; k < CPU_VTLB_SIZE; k++) {
tlb_flush_entry(&env->tlb_v_table[mmu_idx][k], addr);
}
tlb_flush_vtlb_page(env, mmu_idx, addr);
}
tb_flush_jmp_cache(cpu, addr);
@ -310,7 +316,6 @@ static void tlb_flush_page_by_mmuidx_async_work(CPUState *cpu,
unsigned long mmu_idx_bitmap = addr_and_mmuidx & ALL_MMUIDX_BITS;
int page = (addr >> TARGET_PAGE_BITS) & (CPU_TLB_SIZE - 1);
int mmu_idx;
int i;
assert_cpu_is_self(cpu);
@ -320,11 +325,7 @@ static void tlb_flush_page_by_mmuidx_async_work(CPUState *cpu,
for (mmu_idx = 0; mmu_idx < NB_MMU_MODES; mmu_idx++) {
if (test_bit(mmu_idx, &mmu_idx_bitmap)) {
tlb_flush_entry(&env->tlb_table[mmu_idx][page], addr);
/* check whether there are vltb entries that need to be flushed */
for (i = 0; i < CPU_VTLB_SIZE; i++) {
tlb_flush_entry(&env->tlb_v_table[mmu_idx][i], addr);
}
tlb_flush_vtlb_page(env, mmu_idx, addr);
}
}
@ -609,10 +610,9 @@ void tlb_set_page_with_attrs(CPUState *cpu, target_ulong vaddr,
target_ulong address;
target_ulong code_address;
uintptr_t addend;
CPUTLBEntry *te, *tv, tn;
CPUTLBEntry *te, tn;
hwaddr iotlb, xlat, sz, paddr_page;
target_ulong vaddr_page;
unsigned vidx = env->vtlb_index++ % CPU_VTLB_SIZE;
int asidx = cpu_asidx_from_attrs(cpu, attrs);
assert_cpu_is_self(cpu);
@ -654,19 +654,28 @@ void tlb_set_page_with_attrs(CPUState *cpu, target_ulong vaddr,
addend = (uintptr_t)memory_region_get_ram_ptr(section->mr) + xlat;
}
/* Make sure there's no cached translation for the new page. */
tlb_flush_vtlb_page(env, mmu_idx, vaddr_page);
code_address = address;
iotlb = memory_region_section_get_iotlb(cpu, section, vaddr_page,
paddr_page, xlat, prot, &address);
index = (vaddr_page >> TARGET_PAGE_BITS) & (CPU_TLB_SIZE - 1);
te = &env->tlb_table[mmu_idx][index];
/* do not discard the translation in te, evict it into a victim tlb */
tv = &env->tlb_v_table[mmu_idx][vidx];
/* addr_write can race with tlb_reset_dirty_range */
copy_tlb_helper(tv, te, true);
/*
* Only evict the old entry to the victim tlb if it's for a
* different page; otherwise just overwrite the stale data.
*/
if (!tlb_hit_page_anyprot(te, vaddr_page)) {
unsigned vidx = env->vtlb_index++ % CPU_VTLB_SIZE;
CPUTLBEntry *tv = &env->tlb_v_table[mmu_idx][vidx];
env->iotlb_v[mmu_idx][vidx] = env->iotlb[mmu_idx][index];
/* Evict the old entry into the victim tlb. */
copy_tlb_helper(tv, te, true);
env->iotlb_v[mmu_idx][vidx] = env->iotlb[mmu_idx][index];
}
/* refill the tlb */
/*