From 5601be3b01d73e21c09331599e2ce62df016ff94 Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Fri, 1 Feb 2019 14:55:45 +0000 Subject: [PATCH] exec.c: Don't reallocate IOMMUNotifiers that are in use The tcg_register_iommu_notifier() code has a GArray of TCGIOMMUNotifier structs which it has registered by passing memory_region_register_iommu_notifier() a pointer to the embedded IOMMUNotifier field. Unfortunately, if we need to enlarge the array via g_array_set_size() this can cause a realloc(), which invalidates the pointer that memory_region_register_iommu_notifier() put into the MemoryRegion's iommu_notify list. This can result in segfaults. Switch the GArray to holding pointers to the TCGIOMMUNotifier structs, so that we can individually allocate and free them. Cc: qemu-stable@nongnu.org Fixes: 1f871c5e6b0f30644a60a ("exec.c: Handle IOMMUs in address_space_translate_for_iotlb()") Signed-off-by: Peter Maydell Reviewed-by: Richard Henderson Message-id: 20190128174241.5860-1-peter.maydell@linaro.org --- exec.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/exec.c b/exec.c index da3e635f91b..25f3938a271 100644 --- a/exec.c +++ b/exec.c @@ -665,7 +665,7 @@ static void tcg_register_iommu_notifier(CPUState *cpu, int i; for (i = 0; i < cpu->iommu_notifiers->len; i++) { - notifier = &g_array_index(cpu->iommu_notifiers, TCGIOMMUNotifier, i); + notifier = g_array_index(cpu->iommu_notifiers, TCGIOMMUNotifier *, i); if (notifier->mr == mr && notifier->iommu_idx == iommu_idx) { break; } @@ -673,7 +673,8 @@ static void tcg_register_iommu_notifier(CPUState *cpu, if (i == cpu->iommu_notifiers->len) { /* Not found, add a new entry at the end of the array */ cpu->iommu_notifiers = g_array_set_size(cpu->iommu_notifiers, i + 1); - notifier = &g_array_index(cpu->iommu_notifiers, TCGIOMMUNotifier, i); + notifier = g_new0(TCGIOMMUNotifier, 1); + g_array_index(cpu->iommu_notifiers, TCGIOMMUNotifier *, i) = notifier; notifier->mr = mr; notifier->iommu_idx = iommu_idx; @@ -705,8 +706,9 @@ static void tcg_iommu_free_notifier_list(CPUState *cpu) TCGIOMMUNotifier *notifier; for (i = 0; i < cpu->iommu_notifiers->len; i++) { - notifier = &g_array_index(cpu->iommu_notifiers, TCGIOMMUNotifier, i); + notifier = g_array_index(cpu->iommu_notifiers, TCGIOMMUNotifier *, i); memory_region_unregister_iommu_notifier(notifier->mr, ¬ifier->n); + g_free(notifier); } g_array_free(cpu->iommu_notifiers, true); } @@ -976,7 +978,7 @@ void cpu_exec_realizefn(CPUState *cpu, Error **errp) vmstate_register(NULL, cpu->cpu_index, cc->vmsd, cpu); } - cpu->iommu_notifiers = g_array_new(false, true, sizeof(TCGIOMMUNotifier)); + cpu->iommu_notifiers = g_array_new(false, true, sizeof(TCGIOMMUNotifier *)); #endif } -- 2.39.5