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-rw-r--r--accel/tcg/cputlb.c155
-rw-r--r--include/exec/cpu-defs.h3
2 files changed, 87 insertions, 71 deletions
diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c
index f6b388c..c2a6190 100644
--- a/accel/tcg/cputlb.c
+++ b/accel/tcg/cputlb.c
@@ -75,6 +75,9 @@ QEMU_BUILD_BUG_ON(NB_MMU_MODES > 16);
void tlb_init(CPUState *cpu)
{
+ CPUArchState *env = cpu->env_ptr;
+
+ qemu_spin_init(&env->tlb_lock);
}
/* flush_all_helper: run fn across all cpus
@@ -129,8 +132,17 @@ static void tlb_flush_nocheck(CPUState *cpu)
atomic_set(&env->tlb_flush_count, env->tlb_flush_count + 1);
tlb_debug("(count: %zu)\n", tlb_flush_count());
+ /*
+ * tlb_table/tlb_v_table updates from any thread must hold tlb_lock.
+ * However, updates from the owner thread (as is the case here; see the
+ * above assert_cpu_is_self) do not need atomic_set because all reads
+ * that do not hold the lock are performed by the same owner thread.
+ */
+ qemu_spin_lock(&env->tlb_lock);
memset(env->tlb_table, -1, sizeof(env->tlb_table));
memset(env->tlb_v_table, -1, sizeof(env->tlb_v_table));
+ qemu_spin_unlock(&env->tlb_lock);
+
cpu_tb_jmp_cache_clear(cpu);
env->vtlb_index = 0;
@@ -182,6 +194,7 @@ static void tlb_flush_by_mmuidx_async_work(CPUState *cpu, run_on_cpu_data data)
tlb_debug("start: mmu_idx:0x%04lx\n", mmu_idx_bitmask);
+ qemu_spin_lock(&env->tlb_lock);
for (mmu_idx = 0; mmu_idx < NB_MMU_MODES; mmu_idx++) {
if (test_bit(mmu_idx, &mmu_idx_bitmask)) {
@@ -191,6 +204,7 @@ static void tlb_flush_by_mmuidx_async_work(CPUState *cpu, run_on_cpu_data data)
memset(env->tlb_v_table[mmu_idx], -1, sizeof(env->tlb_v_table[0]));
}
}
+ qemu_spin_unlock(&env->tlb_lock);
cpu_tb_jmp_cache_clear(cpu);
@@ -247,19 +261,24 @@ static inline bool tlb_hit_page_anyprot(CPUTLBEntry *tlb_entry,
tlb_hit_page(tlb_entry->addr_code, page);
}
-static inline void tlb_flush_entry(CPUTLBEntry *tlb_entry, target_ulong page)
+/* Called with tlb_lock held */
+static inline void tlb_flush_entry_locked(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)
+/* Called with tlb_lock held */
+static inline void tlb_flush_vtlb_page_locked(CPUArchState *env, int mmu_idx,
+ target_ulong page)
{
int k;
+
+ assert_cpu_is_self(ENV_GET_CPU(env));
for (k = 0; k < CPU_VTLB_SIZE; k++) {
- tlb_flush_entry(&env->tlb_v_table[mmu_idx][k], page);
+ tlb_flush_entry_locked(&env->tlb_v_table[mmu_idx][k], page);
}
}
@@ -286,10 +305,12 @@ static void tlb_flush_page_async_work(CPUState *cpu, run_on_cpu_data data)
addr &= TARGET_PAGE_MASK;
i = (addr >> TARGET_PAGE_BITS) & (CPU_TLB_SIZE - 1);
+ qemu_spin_lock(&env->tlb_lock);
for (mmu_idx = 0; mmu_idx < NB_MMU_MODES; mmu_idx++) {
- tlb_flush_entry(&env->tlb_table[mmu_idx][i], addr);
- tlb_flush_vtlb_page(env, mmu_idx, addr);
+ tlb_flush_entry_locked(&env->tlb_table[mmu_idx][i], addr);
+ tlb_flush_vtlb_page_locked(env, mmu_idx, addr);
}
+ qemu_spin_unlock(&env->tlb_lock);
tb_flush_jmp_cache(cpu, addr);
}
@@ -326,12 +347,14 @@ static void tlb_flush_page_by_mmuidx_async_work(CPUState *cpu,
tlb_debug("page:%d addr:"TARGET_FMT_lx" mmu_idx:0x%lx\n",
page, addr, mmu_idx_bitmap);
+ qemu_spin_lock(&env->tlb_lock);
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);
- tlb_flush_vtlb_page(env, mmu_idx, addr);
+ tlb_flush_entry_locked(&env->tlb_table[mmu_idx][page], addr);
+ tlb_flush_vtlb_page_locked(env, mmu_idx, addr);
}
}
+ qemu_spin_unlock(&env->tlb_lock);
tb_flush_jmp_cache(cpu, addr);
}
@@ -454,72 +477,44 @@ void tlb_unprotect_code(ram_addr_t ram_addr)
* most usual is detecting writes to code regions which may invalidate
* generated code.
*
- * Because we want other vCPUs to respond to changes straight away we
- * update the te->addr_write field atomically. If the TLB entry has
- * been changed by the vCPU in the mean time we skip the update.
+ * Other vCPUs might be reading their TLBs during guest execution, so we update
+ * te->addr_write with atomic_set. We don't need to worry about this for
+ * oversized guests as MTTCG is disabled for them.
*
- * As this function uses atomic accesses we also need to ensure
- * updates to tlb_entries follow the same access rules. We don't need
- * to worry about this for oversized guests as MTTCG is disabled for
- * them.
+ * Called with tlb_lock held.
*/
-
-static void tlb_reset_dirty_range(CPUTLBEntry *tlb_entry, uintptr_t start,
- uintptr_t length)
+static void tlb_reset_dirty_range_locked(CPUTLBEntry *tlb_entry,
+ uintptr_t start, uintptr_t length)
{
-#if TCG_OVERSIZED_GUEST
uintptr_t addr = tlb_entry->addr_write;
if ((addr & (TLB_INVALID_MASK | TLB_MMIO | TLB_NOTDIRTY)) == 0) {
addr &= TARGET_PAGE_MASK;
addr += tlb_entry->addend;
if ((addr - start) < length) {
+#if TCG_OVERSIZED_GUEST
tlb_entry->addr_write |= TLB_NOTDIRTY;
- }
- }
#else
- /* paired with atomic_mb_set in tlb_set_page_with_attrs */
- uintptr_t orig_addr = atomic_mb_read(&tlb_entry->addr_write);
- uintptr_t addr = orig_addr;
-
- if ((addr & (TLB_INVALID_MASK | TLB_MMIO | TLB_NOTDIRTY)) == 0) {
- addr &= TARGET_PAGE_MASK;
- addr += atomic_read(&tlb_entry->addend);
- if ((addr - start) < length) {
- uintptr_t notdirty_addr = orig_addr | TLB_NOTDIRTY;
- atomic_cmpxchg(&tlb_entry->addr_write, orig_addr, notdirty_addr);
+ atomic_set(&tlb_entry->addr_write,
+ tlb_entry->addr_write | TLB_NOTDIRTY);
+#endif
}
}
-#endif
}
-/* For atomic correctness when running MTTCG we need to use the right
- * primitives when copying entries */
-static inline void copy_tlb_helper(CPUTLBEntry *d, CPUTLBEntry *s,
- bool atomic_set)
+/*
+ * Called with tlb_lock held.
+ * Called only from the vCPU context, i.e. the TLB's owner thread.
+ */
+static inline void copy_tlb_helper_locked(CPUTLBEntry *d, const CPUTLBEntry *s)
{
-#if TCG_OVERSIZED_GUEST
*d = *s;
-#else
- if (atomic_set) {
- d->addr_read = s->addr_read;
- d->addr_code = s->addr_code;
- atomic_set(&d->addend, atomic_read(&s->addend));
- /* Pairs with flag setting in tlb_reset_dirty_range */
- atomic_mb_set(&d->addr_write, atomic_read(&s->addr_write));
- } else {
- d->addr_read = s->addr_read;
- d->addr_write = atomic_read(&s->addr_write);
- d->addr_code = s->addr_code;
- d->addend = atomic_read(&s->addend);
- }
-#endif
}
/* This is a cross vCPU call (i.e. another vCPU resetting the flags of
- * the target vCPU). As such care needs to be taken that we don't
- * dangerously race with another vCPU update. The only thing actually
- * updated is the target TLB entry ->addr_write flags.
+ * the target vCPU).
+ * We must take tlb_lock to avoid racing with another vCPU update. The only
+ * thing actually updated is the target TLB entry ->addr_write flags.
*/
void tlb_reset_dirty(CPUState *cpu, ram_addr_t start1, ram_addr_t length)
{
@@ -528,22 +523,26 @@ void tlb_reset_dirty(CPUState *cpu, ram_addr_t start1, ram_addr_t length)
int mmu_idx;
env = cpu->env_ptr;
+ qemu_spin_lock(&env->tlb_lock);
for (mmu_idx = 0; mmu_idx < NB_MMU_MODES; mmu_idx++) {
unsigned int i;
for (i = 0; i < CPU_TLB_SIZE; i++) {
- tlb_reset_dirty_range(&env->tlb_table[mmu_idx][i],
- start1, length);
+ tlb_reset_dirty_range_locked(&env->tlb_table[mmu_idx][i], start1,
+ length);
}
for (i = 0; i < CPU_VTLB_SIZE; i++) {
- tlb_reset_dirty_range(&env->tlb_v_table[mmu_idx][i],
- start1, length);
+ tlb_reset_dirty_range_locked(&env->tlb_v_table[mmu_idx][i], start1,
+ length);
}
}
+ qemu_spin_unlock(&env->tlb_lock);
}
-static inline void tlb_set_dirty1(CPUTLBEntry *tlb_entry, target_ulong vaddr)
+/* Called with tlb_lock held */
+static inline void tlb_set_dirty1_locked(CPUTLBEntry *tlb_entry,
+ target_ulong vaddr)
{
if (tlb_entry->addr_write == (vaddr | TLB_NOTDIRTY)) {
tlb_entry->addr_write = vaddr;
@@ -562,16 +561,18 @@ void tlb_set_dirty(CPUState *cpu, target_ulong vaddr)
vaddr &= TARGET_PAGE_MASK;
i = (vaddr >> TARGET_PAGE_BITS) & (CPU_TLB_SIZE - 1);
+ qemu_spin_lock(&env->tlb_lock);
for (mmu_idx = 0; mmu_idx < NB_MMU_MODES; mmu_idx++) {
- tlb_set_dirty1(&env->tlb_table[mmu_idx][i], vaddr);
+ tlb_set_dirty1_locked(&env->tlb_table[mmu_idx][i], vaddr);
}
for (mmu_idx = 0; mmu_idx < NB_MMU_MODES; mmu_idx++) {
int k;
for (k = 0; k < CPU_VTLB_SIZE; k++) {
- tlb_set_dirty1(&env->tlb_v_table[mmu_idx][k], vaddr);
+ tlb_set_dirty1_locked(&env->tlb_v_table[mmu_idx][k], vaddr);
}
}
+ qemu_spin_unlock(&env->tlb_lock);
}
/* Our TLB does not support large pages, so remember the area covered by
@@ -658,9 +659,6 @@ 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);
@@ -669,6 +667,18 @@ void tlb_set_page_with_attrs(CPUState *cpu, target_ulong vaddr,
te = &env->tlb_table[mmu_idx][index];
/*
+ * Hold the TLB lock for the rest of the function. We could acquire/release
+ * the lock several times in the function, but it is faster to amortize the
+ * acquisition cost by acquiring it just once. Note that this leads to
+ * a longer critical section, but this is not a concern since the TLB lock
+ * is unlikely to be contended.
+ */
+ qemu_spin_lock(&env->tlb_lock);
+
+ /* Make sure there's no cached translation for the new page. */
+ tlb_flush_vtlb_page_locked(env, mmu_idx, vaddr_page);
+
+ /*
* Only evict the old entry to the victim tlb if it's for a
* different page; otherwise just overwrite the stale data.
*/
@@ -677,7 +687,7 @@ void tlb_set_page_with_attrs(CPUState *cpu, target_ulong vaddr,
CPUTLBEntry *tv = &env->tlb_v_table[mmu_idx][vidx];
/* Evict the old entry into the victim tlb. */
- copy_tlb_helper(tv, te, true);
+ copy_tlb_helper_locked(tv, te);
env->iotlb_v[mmu_idx][vidx] = env->iotlb[mmu_idx][index];
}
@@ -729,9 +739,8 @@ void tlb_set_page_with_attrs(CPUState *cpu, target_ulong vaddr,
}
}
- /* Pairs with flag setting in tlb_reset_dirty_range */
- copy_tlb_helper(te, &tn, true);
- /* atomic_mb_set(&te->addr_write, write_address); */
+ copy_tlb_helper_locked(te, &tn);
+ qemu_spin_unlock(&env->tlb_lock);
}
/* Add a new TLB entry, but without specifying the memory
@@ -895,6 +904,8 @@ static bool victim_tlb_hit(CPUArchState *env, size_t mmu_idx, size_t index,
size_t elt_ofs, target_ulong page)
{
size_t vidx;
+
+ assert_cpu_is_self(ENV_GET_CPU(env));
for (vidx = 0; vidx < CPU_VTLB_SIZE; ++vidx) {
CPUTLBEntry *vtlb = &env->tlb_v_table[mmu_idx][vidx];
target_ulong cmp = *(target_ulong *)((uintptr_t)vtlb + elt_ofs);
@@ -903,9 +914,11 @@ static bool victim_tlb_hit(CPUArchState *env, size_t mmu_idx, size_t index,
/* Found entry in victim tlb, swap tlb and iotlb. */
CPUTLBEntry tmptlb, *tlb = &env->tlb_table[mmu_idx][index];
- copy_tlb_helper(&tmptlb, tlb, false);
- copy_tlb_helper(tlb, vtlb, true);
- copy_tlb_helper(vtlb, &tmptlb, true);
+ qemu_spin_lock(&env->tlb_lock);
+ copy_tlb_helper_locked(&tmptlb, tlb);
+ copy_tlb_helper_locked(tlb, vtlb);
+ copy_tlb_helper_locked(vtlb, &tmptlb);
+ qemu_spin_unlock(&env->tlb_lock);
CPUIOTLBEntry tmpio, *io = &env->iotlb[mmu_idx][index];
CPUIOTLBEntry *vio = &env->iotlb_v[mmu_idx][vidx];
diff --git a/include/exec/cpu-defs.h b/include/exec/cpu-defs.h
index a171ffc..4ff62f3 100644
--- a/include/exec/cpu-defs.h
+++ b/include/exec/cpu-defs.h
@@ -24,6 +24,7 @@
#endif
#include "qemu/host-utils.h"
+#include "qemu/thread.h"
#include "qemu/queue.h"
#ifdef CONFIG_TCG
#include "tcg-target.h"
@@ -142,6 +143,8 @@ typedef struct CPUIOTLBEntry {
#define CPU_COMMON_TLB \
/* The meaning of the MMU modes is defined in the target code. */ \
+ /* tlb_lock serializes updates to tlb_table and tlb_v_table */ \
+ QemuSpin tlb_lock; \
CPUTLBEntry tlb_table[NB_MMU_MODES][CPU_TLB_SIZE]; \
CPUTLBEntry tlb_v_table[NB_MMU_MODES][CPU_VTLB_SIZE]; \
CPUIOTLBEntry iotlb[NB_MMU_MODES][CPU_TLB_SIZE]; \
generated by cgit v1.1 at 2024-12-27 14:01:45 +0000