2 files changed, 95 insertions, 21 deletions

diff --git a/lib/libvmmapi/vmmapi.c b/lib/libvmmapi/vmmapi.c
index 6a368b3..6982ba3 100644
--- a/lib/libvmmapi/vmmapi.c
+++ b/lib/libvmmapi/vmmapi.c
@@ -48,8 +48,16 @@ __FBSDID("$FreeBSD$");
 
 #include "vmmapi.h"
 
+#define	GB	(1024 * 1024 * 1024UL)
+
 struct vmctx {
 	int	fd;
+	uint32_t lowmem_limit;
+	enum vm_mmap_style vms;
+	size_t	lowmem;
+	char	*lowmem_addr;
+	size_t	highmem;
+	char	*highmem_addr;
 	char	*name;
 };
 
@@ -90,6 +98,7 @@ vm_open(const char *name)
 	assert(vm != NULL);
 
 	vm->fd = -1;
+	vm->lowmem_limit = 3 * GB;
 	vm->name = (char *)(vm + 1);
 	strcpy(vm->name, name);
 
@@ -151,8 +160,22 @@ vm_get_memory_seg(struct vmctx *ctx, vm_paddr_t gpa, size_t *ret_len)
 	return (error);
 }
 
-int
-vm_setup_memory(struct vmctx *ctx, vm_paddr_t gpa, size_t len, char **mapaddr)
+uint32_t
+vm_get_lowmem_limit(struct vmctx *ctx)
+{
+
+	return (ctx->lowmem_limit);
+}
+
+void
+vm_set_lowmem_limit(struct vmctx *ctx, uint32_t limit)
+{
+
+	ctx->lowmem_limit = limit;
+}
+
+static int
+setup_memory_segment(struct vmctx *ctx, vm_paddr_t gpa, size_t len, char **addr)
 {
 	int error;
 	struct vm_memory_segment seg;
@@ -165,20 +188,69 @@ vm_setup_memory(struct vmctx *ctx, vm_paddr_t gpa, size_t len, char **mapaddr)
 	seg.gpa = gpa;
 	seg.len = len;
 	error = ioctl(ctx->fd, VM_MAP_MEMORY, &seg);
-	if (error == 0 && mapaddr != NULL) {
-		*mapaddr = mmap(NULL, len, PROT_READ | PROT_WRITE, MAP_SHARED,
+	if (error == 0 && addr != NULL) {
+		*addr = mmap(NULL, len, PROT_READ | PROT_WRITE, MAP_SHARED,
 				ctx->fd, gpa);
 	}
 	return (error);
 }
 
-char *
-vm_map_memory(struct vmctx *ctx, vm_paddr_t gpa, size_t len)
+int
+vm_setup_memory(struct vmctx *ctx, size_t memsize, enum vm_mmap_style vms)
+{
+	char **addr;
+	int error;
+
+	/* XXX VM_MMAP_SPARSE not implemented yet */
+	assert(vms == VM_MMAP_NONE || vms == VM_MMAP_ALL);
+	ctx->vms = vms;
+
+	/*
+	 * If 'memsize' cannot fit entirely in the 'lowmem' segment then
+	 * create another 'highmem' segment above 4GB for the remainder.
+	 */
+	if (memsize > ctx->lowmem_limit) {
+		ctx->lowmem = ctx->lowmem_limit;
+		ctx->highmem = memsize - ctx->lowmem;
+	} else {
+		ctx->lowmem = memsize;
+		ctx->highmem = 0;
+	}
+
+	if (ctx->lowmem > 0) {
+		addr = (vms == VM_MMAP_ALL) ? &ctx->lowmem_addr : NULL;
+		error = setup_memory_segment(ctx, 0, ctx->lowmem, addr);
+		if (error)
+			return (error);
+	}
+
+	if (ctx->highmem > 0) {
+		addr = (vms == VM_MMAP_ALL) ? &ctx->highmem_addr : NULL;
+		error = setup_memory_segment(ctx, 4*GB, ctx->highmem, addr);
+		if (error)
+			return (error);
+	}
+
+	return (0);
+}
+
+void *
+vm_map_gpa(struct vmctx *ctx, vm_paddr_t gaddr, size_t len)
 {
 
-	/* Map 'len' bytes of memory at guest physical address 'gpa' */
-	return ((char *)mmap(NULL, len, PROT_READ | PROT_WRITE, MAP_SHARED,
-		     ctx->fd, gpa));
+	/* XXX VM_MMAP_SPARSE not implemented yet */
+	assert(ctx->vms == VM_MMAP_ALL);
+
+	if (gaddr < ctx->lowmem && gaddr + len <= ctx->lowmem)
+		return ((void *)(ctx->lowmem_addr + gaddr));
+
+	if (gaddr >= 4*GB) {
+		gaddr -= 4*GB;
+		if (gaddr < ctx->highmem && gaddr + len <= ctx->highmem)
+			return ((void *)(ctx->highmem_addr + gaddr));
+	}
+
+	return (NULL);
 }
 
 int
diff --git a/lib/libvmmapi/vmmapi.h b/lib/libvmmapi/vmmapi.h
index e8cc8ba..f066c50 100644
--- a/lib/libvmmapi/vmmapi.h
+++ b/lib/libvmmapi/vmmapi.h
@@ -32,24 +32,26 @@
 struct vmctx;
 enum x2apic_state;
 
+/*
+ * Different styles of mapping the memory assigned to a VM into the address
+ * space of the controlling process.
+ */
+enum vm_mmap_style {
+	VM_MMAP_NONE,		/* no mapping */
+	VM_MMAP_ALL,		/* fully and statically mapped */
+	VM_MMAP_SPARSE,		/* mappings created on-demand */
+};
+
 int	vm_create(const char *name);
 struct vmctx *vm_open(const char *name);
 void	vm_destroy(struct vmctx *ctx);
 size_t	vmm_get_mem_total(void);
 size_t	vmm_get_mem_free(void);
 int	vm_get_memory_seg(struct vmctx *ctx, vm_paddr_t gpa, size_t *ret_len);
-/*
- * Create a memory segment of 'len' bytes in the guest physical address space
- * at offset 'gpa'.
- *
- * If 'mapaddr' is not NULL then this region is mmap'ed into the address
- * space of the calling process. If there is an mmap error then *mapaddr
- * will be set to MAP_FAILED.
- */
-
-int	vm_setup_memory(struct vmctx *ctx, vm_paddr_t gpa, size_t len,
-		      char **mapaddr);
-char *  vm_map_memory(struct vmctx *ctx, vm_paddr_t gpa, size_t len);
+int	vm_setup_memory(struct vmctx *ctx, size_t len, enum vm_mmap_style s);
+void	*vm_map_gpa(struct vmctx *ctx, vm_paddr_t gaddr, size_t len);
+uint32_t vm_get_lowmem_limit(struct vmctx *ctx);
+void	vm_set_lowmem_limit(struct vmctx *ctx, uint32_t limit);
 int	vm_set_desc(struct vmctx *ctx, int vcpu, int reg,
 		    uint64_t base, uint32_t limit, uint32_t access);
 int	vm_get_desc(struct vmctx *ctx, int vcpu, int reg,