diff mbox series

[RFC,03/19] RAMBlock: Support KVM gmemory

Message ID 20230731162201.271114-4-xiaoyao.li@intel.com (mailing list archive)
State New, archived
Headers show
Series QEMU gmem implemention | expand

Commit Message

Xiaoyao Li July 31, 2023, 4:21 p.m. UTC 
From: Chao Peng <chao.p.peng@linux.intel.com>

Add KVM gmem support to RAMBlock so we can have both normal
hva based memory and gmem fd based memory in one RAMBlock.

The gmem part is represented by the gmem_fd.

Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com>
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
---
 include/exec/memory.h   | 8 ++++++++
 include/exec/ramblock.h | 1 +
 softmmu/memory.c        | 9 +++++++++
 softmmu/physmem.c       | 2 ++
 4 files changed, 20 insertions(+)

Comments

David Hildenbrand Aug. 1, 2023, 4:33 p.m. UTC | #1 
On 31.07.23 18:21, Xiaoyao Li wrote:
> From: Chao Peng <chao.p.peng@linux.intel.com>
> 
> Add KVM gmem support to RAMBlock so we can have both normal
> hva based memory and gmem fd based memory in one RAMBlock.
> 
> The gmem part is represented by the gmem_fd.
> 
> Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com>
> Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>

So, *someone* creates a RAMBlock in QEMU.

Who'll squeeze a gmem_fd in there? When? How?

Shouldn't we create the RAM memory region / RAMBlock already with the 
gmem_fd, and set that when initializing these things?
diff mbox series

Patch

diff --git a/include/exec/memory.h b/include/exec/memory.h
index 7f5c11a0cc9e..61e31c7b9874 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -1376,6 +1376,14 @@  void memory_region_init_ram_from_fd(MemoryRegion *mr,
                                     int fd,
                                     ram_addr_t offset,
                                     Error **errp);
+/**
+ * memory_region_set_gmem_fd:  Set RAM memory region with a restricted fd.
+ *
+ * @mr: the #MemoryRegion to be set.
+ * @fd: the fd to provide restricted memory.
+ */
+void memory_region_set_gmem_fd(MemoryRegion *mr, int fd);
+
 #endif
 
 /**
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/softmmu/memory.c b/softmmu/memory.c
index 7d9494ce7028..4f8f8c0a02e6 100644
--- a/softmmu/memory.c
+++ b/softmmu/memory.c
@@ -1661,6 +1661,15 @@  void memory_region_init_ram_from_fd(MemoryRegion *mr,
         error_propagate(errp, err);
     }
 }
+
+void memory_region_set_gmem_fd(MemoryRegion *mr, int fd)
+{
+    if (mr->ram_block) {
+        assert(fd >= 0);
+        mr->ram_block->gmem_fd = fd;
+    }
+}
+
 #endif
 
 void memory_region_init_ram_ptr(MemoryRegion *mr,
diff --git a/softmmu/physmem.c b/softmmu/physmem.c
index 3df73542e1fe..8f64128de0b5 100644
--- a/softmmu/physmem.c
+++ b/softmmu/physmem.c
@@ -1920,6 +1920,7 @@  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) {
@@ -1990,6 +1991,7 @@  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;