From: Ming Lin <ming.l@xxxxxxxxxxxxxxx>
This borrows code from Hannes Reinecke's rts-megasas.
Cc: Hannes Reinecke <hare@xxxxxxx>
Signed-off-by: Ming Lin <ming.l@xxxxxxxxxxxxxxx>
---
drivers/nvme/target/vhost.c | 108 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 108 insertions(+)
diff --git a/drivers/nvme/target/vhost.c b/drivers/nvme/target/vhost.c
index 04ed0bc..6847c86 100644
--- a/drivers/nvme/target/vhost.c
+++ b/drivers/nvme/target/vhost.c
@@ -5,6 +5,7 @@
#include <linux/miscdevice.h>
#include <linux/mutex.h>
#include <linux/file.h>
+#include <linux/highmem.h>
#include "../../vhost/vhost.h"
#include "nvmet.h"
@@ -95,6 +96,113 @@ struct nvmet_vhost_ctrl {
u32 page_size;
};
+const struct vhost_memory_region *
+find_region(struct vhost_dev *hba, __u64 addr, __u32 len)
+{
+ struct vhost_memory *mem;
+ struct vhost_memory_region *reg;
+ int i;
+
+ if (!hba->memory)
+ return NULL;
+
+ mem = hba->memory;
+ /* linear search is not brilliant, but we really have on the order of 6
+ * regions in practice */
+ for (i = 0; i < mem->nregions; ++i) {
+ reg = mem->regions + i;
+ if (reg->guest_phys_addr <= addr &&
+ reg->guest_phys_addr + reg->memory_size - 1 >= addr)
+ return reg;
+ }
+ return NULL;
+}
+
+static bool check_region_boundary(const struct vhost_memory_region *reg,
+ uint64_t addr, size_t len)
+{
+ unsigned long max_size;
+
+ max_size = reg->memory_size - addr + reg->guest_phys_addr;
+ return (max_size < len);
+}
+
+static void __user *map_to_region(const struct vhost_memory_region *reg,
+ uint64_t addr)
+{
+ return (void __user *)(unsigned long)
+ (reg->userspace_addr + addr - reg->guest_phys_addr);
+}
+
+static void __user *map_guest_to_host(struct vhost_dev *dev,
+ uint64_t addr, int size)
+{
+ const struct vhost_memory_region *reg = NULL;
+
+ reg = find_region(dev, addr, size);
+ if (unlikely(!reg))
+ return ERR_PTR(-EPERM);
+
+ if (unlikely(check_region_boundary(reg, addr, size)))
+ return ERR_PTR(-EFAULT);
+
+ return map_to_region(reg, addr);
+}
+
+static int nvmet_vhost_rw(struct vhost_dev *dev, u64 guest_pa,
+ void *buf, uint32_t size, int write)
+{
+ void __user *host_user_va;
+ void *host_kernel_va;
+ struct page *page;
+ uintptr_t offset;
+ int ret;
+
+ host_user_va = map_guest_to_host(dev, guest_pa, size);
+ if (unlikely(!host_user_va)) {
+ pr_warn("cannot map guest addr %p, error %ld\n",
+ (void *)guest_pa, PTR_ERR(host_user_va));
+ return -EINVAL;
+ }
+
+ ret = get_user_pages(current, dev->mm,
+ (unsigned long)host_user_va, 1,
+ false, 0, &page, NULL);
+ if (unlikely(ret != 1)) {
+ pr_warn("get_user_pages fail!!!\n");
+ return -EINVAL;
+ }
+
+ host_kernel_va = kmap(page);
+ if (unlikely(!host_kernel_va)) {
+ pr_warn("kmap fail!!!\n");
+ put_page(page);
+ return -EINVAL;
+ }
+
+ offset = (uintptr_t)host_user_va & ~PAGE_MASK;
+ if (write)
+ memcpy(host_kernel_va + offset, buf, size);
+ else
+ memcpy(buf, host_kernel_va + offset, size);
+ kunmap(host_kernel_va);
+ put_page(page);
+
+ return 0;
+}
+
+int nvmet_vhost_read(struct vhost_dev *dev, u64 guest_pa,
+ void *buf, uint32_t size)
+{
+ return nvmet_vhost_rw(dev, guest_pa, buf, size, 0);
+}
+
+int nvmet_vhost_write(struct vhost_dev *dev, u64 guest_pa,
+ void *buf, uint32_t size)
+{
+ return nvmet_vhost_rw(dev, guest_pa, buf, size, 1);
+}
+
#define sq_to_vsq(sq) container_of(sq, struct nvmet_vhost_sq, sq)
#define cq_to_vcq(cq) container_of(cq, struct nvmet_vhost_cq, cq)
--
1.9.1
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