From: Chao Peng <chao.p.peng@xxxxxxxxxxxxxxx>
Add KVM gmem support to RAMBlock so both normal hva based memory
and kvm gmem fd based private memory can be associated in one RAMBlock.
Introduce new flag RAM_KVM_GMEM. It calls KVM ioctl to create private
gmem for the RAMBlock when it's set.
Signed-off-by: Xiaoyao Li <xiaoyao.li@xxxxxxxxx>
---
accel/kvm/kvm-all.c | 17 +++++++++++++++++
include/exec/memory.h | 3 +++
include/exec/ramblock.h | 1 +
include/sysemu/kvm.h | 2 ++
softmmu/physmem.c | 18 +++++++++++++++---
5 files changed, 38 insertions(+), 3 deletions(-)
diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index 60aacd925393..185ae16d9620 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -4225,3 +4225,20 @@ void query_stats_schemas_cb(StatsSchemaList **result, Error **errp)
query_stats_schema_vcpu(first_cpu, &stats_args);
}
}
+
+int kvm_create_guest_memfd(uint64_t size, uint64_t flags, Error **errp)
+{
+ int fd;
+ struct kvm_create_guest_memfd gmem = {
+ .size = size,
+ /* TODO: to decide whether KVM_GUEST_MEMFD_ALLOW_HUGEPAGE is supported */
+ .flags = flags,
+ };
+
+ fd = kvm_vm_ioctl(kvm_state, KVM_CREATE_GUEST_MEMFD, &gmem);
+ if (fd < 0) {
+ error_setg_errno(errp, errno, "%s: error creating kvm gmem\n", __func__);
+ }
+
+ return fd;
+}
diff --git a/include/exec/memory.h b/include/exec/memory.h
index 68284428f87c..227cb2578e95 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -235,6 +235,9 @@ typedef struct IOMMUTLBEvent {
/* RAM is an mmap-ed named file */
#define RAM_NAMED_FILE (1 << 9)
+/* RAM can be private that has kvm gmem backend */
+#define RAM_KVM_GMEM (1 << 10)
+
static inline void iommu_notifier_init(IOMMUNotifier *n, IOMMUNotify fn,
IOMMUNotifierFlag flags,
hwaddr start, hwaddr end,
diff --git a/include/exec/ramblock.h b/include/exec/ramblock.h
index 69c6a5390293..0d158b3909c9 100644
--- a/include/exec/ramblock.h
+++ b/include/exec/ramblock.h
@@ -41,6 +41,7 @@ struct RAMBlock {
QLIST_HEAD(, RAMBlockNotifier) ramblock_notifiers;
int fd;
uint64_t fd_offset;
+ int gmem_fd;
size_t page_size;
/* dirty bitmap used during migration */
unsigned long *bmap;
diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h
index 115f0cca79d1..f5b74c8dd8c5 100644
--- a/include/sysemu/kvm.h
+++ b/include/sysemu/kvm.h
@@ -580,4 +580,6 @@ bool kvm_arch_cpu_check_are_resettable(void);
bool kvm_dirty_ring_enabled(void);
uint32_t kvm_dirty_ring_size(void);
+
+int kvm_create_guest_memfd(uint64_t size, uint64_t flags, Error **errp);
#endif
diff --git a/softmmu/physmem.c b/softmmu/physmem.c
index 3df73542e1fe..2d98a88f41f0 100644
--- a/softmmu/physmem.c
+++ b/softmmu/physmem.c
@@ -1824,6 +1824,16 @@ static void ram_block_add(RAMBlock *new_block, Error **errp)
}
}
+ if (kvm_enabled() && new_block->flags & RAM_KVM_GMEM &&
+ new_block->gmem_fd < 0) {
+ new_block->gmem_fd = kvm_create_guest_memfd(new_block->max_length,
+ 0, errp);
+ if (new_block->gmem_fd < 0) {
+ qemu_mutex_unlock_ramlist();
+ return;
+ }
+ }
+
new_ram_size = MAX(old_ram_size,
(new_block->offset + new_block->max_length) >> TARGET_PAGE_BITS);
if (new_ram_size > old_ram_size) {
@@ -1885,7 +1895,7 @@ RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, MemoryRegion *mr,
/* Just support these ram flags by now. */
assert((ram_flags & ~(RAM_SHARED | RAM_PMEM | RAM_NORESERVE |
- RAM_PROTECTED | RAM_NAMED_FILE)) == 0);
+ RAM_PROTECTED | RAM_NAMED_FILE | RAM_KVM_GMEM)) == 0);
if (xen_enabled()) {
error_setg(errp, "-mem-path not supported with Xen");
@@ -1920,6 +1930,7 @@ RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, MemoryRegion *mr,
new_block->used_length = size;
new_block->max_length = size;
new_block->flags = ram_flags;
+ new_block->gmem_fd = -1;
new_block->host = file_ram_alloc(new_block, size, fd, readonly,
!file_size, offset, errp);
if (!new_block->host) {
@@ -1978,7 +1989,7 @@ RAMBlock *qemu_ram_alloc_internal(ram_addr_t size, ram_addr_t max_size,
Error *local_err = NULL;
assert((ram_flags & ~(RAM_SHARED | RAM_RESIZEABLE | RAM_PREALLOC |
- RAM_NORESERVE)) == 0);
+ RAM_NORESERVE| RAM_KVM_GMEM)) == 0);
assert(!host ^ (ram_flags & RAM_PREALLOC));
size = HOST_PAGE_ALIGN(size);
@@ -1990,6 +2001,7 @@ RAMBlock *qemu_ram_alloc_internal(ram_addr_t size, ram_addr_t max_size,
new_block->max_length = max_size;
assert(max_size >= size);
new_block->fd = -1;
+ new_block->gmem_fd = -1;
new_block->page_size = qemu_real_host_page_size();
new_block->host = host;
new_block->flags = ram_flags;
@@ -2012,7 +2024,7 @@ RAMBlock *qemu_ram_alloc_from_ptr(ram_addr_t size, void *host,
RAMBlock *qemu_ram_alloc(ram_addr_t size, uint32_t ram_flags,
MemoryRegion *mr, Error **errp)
{
- assert((ram_flags & ~(RAM_SHARED | RAM_NORESERVE)) == 0);
+ assert((ram_flags & ~(RAM_SHARED | RAM_NORESERVE | RAM_KVM_GMEM)) == 0);
return qemu_ram_alloc_internal(size, size, NULL, NULL, ram_flags, mr, errp);
}
--
2.34.1
