From 6c090d4a755bb6245461450869130a517e18a3dc Mon Sep 17 00:00:00 2001 From: Shannon Zhao Date: Wed, 16 May 2018 17:18:34 +0800 Subject: [PATCH] kvm: Delete the slot if and only if the KVM_MEM_READONLY flag is changed According to KVM commit 75d61fbc, it needs to delete the slot before changing the KVM_MEM_READONLY flag. But QEMU commit 235e8982 only check whether KVM_MEM_READONLY flag is set instead of changing. It doesn't need to delete the slot if the KVM_MEM_READONLY flag is not changed. This fixes a issue that migrating a VM at the OVMF startup stage and VM is executing the codes in rom. Between the deleting and adding the slot in kvm_set_user_memory_region, there is a chance that guest access rom and trap to KVM, then KVM can't find the corresponding memslot. While KVM (on ARM) injects an abort to guest due to the broken hva, then guest will get stuck. Signed-off-by: Shannon Zhao Message-Id: <1526462314-19720-1-git-send-email-zhaoshenglong@huawei.com> Signed-off-by: Paolo Bonzini --- accel/kvm/kvm-all.c | 17 ++++++++--------- include/sysemu/kvm_int.h | 1 + 2 files changed, 9 insertions(+), 9 deletions(-) diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c index ffee68e603..eb7db92a5e 100644 --- a/accel/kvm/kvm-all.c +++ b/accel/kvm/kvm-all.c @@ -256,7 +256,7 @@ int kvm_physical_memory_addr_from_host(KVMState *s, void *ram, return 0; } -static int kvm_set_user_memory_region(KVMMemoryListener *kml, KVMSlot *slot) +static int kvm_set_user_memory_region(KVMMemoryListener *kml, KVMSlot *slot, bool new) { KVMState *s = kvm_state; struct kvm_userspace_memory_region mem; @@ -267,7 +267,7 @@ static int kvm_set_user_memory_region(KVMMemoryListener *kml, KVMSlot *slot) mem.userspace_addr = (unsigned long)slot->ram; mem.flags = slot->flags; - if (slot->memory_size && mem.flags & KVM_MEM_READONLY) { + if (slot->memory_size && !new && (mem.flags ^ slot->old_flags) & KVM_MEM_READONLY) { /* Set the slot size to 0 before setting the slot to the desired * value. This is needed based on KVM commit 75d61fbc. */ mem.memory_size = 0; @@ -275,6 +275,7 @@ static int kvm_set_user_memory_region(KVMMemoryListener *kml, KVMSlot *slot) } mem.memory_size = slot->memory_size; ret = kvm_vm_ioctl(s, KVM_SET_USER_MEMORY_REGION, &mem); + slot->old_flags = mem.flags; trace_kvm_set_user_memory(mem.slot, mem.flags, mem.guest_phys_addr, mem.memory_size, mem.userspace_addr, ret); return ret; @@ -391,17 +392,14 @@ static int kvm_mem_flags(MemoryRegion *mr) static int kvm_slot_update_flags(KVMMemoryListener *kml, KVMSlot *mem, MemoryRegion *mr) { - int old_flags; - - old_flags = mem->flags; mem->flags = kvm_mem_flags(mr); /* If nothing changed effectively, no need to issue ioctl */ - if (mem->flags == old_flags) { + if (mem->flags == mem->old_flags) { return 0; } - return kvm_set_user_memory_region(kml, mem); + return kvm_set_user_memory_region(kml, mem, false); } static int kvm_section_update_flags(KVMMemoryListener *kml, @@ -755,7 +753,8 @@ static void kvm_set_phys_mem(KVMMemoryListener *kml, /* unregister the slot */ mem->memory_size = 0; - err = kvm_set_user_memory_region(kml, mem); + mem->flags = 0; + err = kvm_set_user_memory_region(kml, mem, false); if (err) { fprintf(stderr, "%s: error unregistering slot: %s\n", __func__, strerror(-err)); @@ -771,7 +770,7 @@ static void kvm_set_phys_mem(KVMMemoryListener *kml, mem->ram = ram; mem->flags = kvm_mem_flags(mr); - err = kvm_set_user_memory_region(kml, mem); + err = kvm_set_user_memory_region(kml, mem, true); if (err) { fprintf(stderr, "%s: error registering slot: %s\n", __func__, strerror(-err)); diff --git a/include/sysemu/kvm_int.h b/include/sysemu/kvm_int.h index 888557a1ca..f838412491 100644 --- a/include/sysemu/kvm_int.h +++ b/include/sysemu/kvm_int.h @@ -20,6 +20,7 @@ typedef struct KVMSlot void *ram; int slot; int flags; + int old_flags; } KVMSlot; typedef struct KVMMemoryListener { -- 2.11.0