From: Pekka Enberg <penberg@kernel.org>
Date: Wed, 5 Jan 2011 17:54:48 +0000 (+0200)
Subject: kvm: Add support for disk images
X-Git-Tag: next-20110824~3^2~528^2~32
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=9297809d5e80e550298bb8c8aeb478b30cf7e0c5;p=karo-tx-linux.git

kvm: Add support for disk images

This patch implements "--image" command line option that can be used to specify
a disk image. It supports raw images and it needs to be integrated to the
hypervisor block layer.

Signed-off-by: Pekka Enberg <penberg@kernel.org>
---

diff --git a/tools/kvm/Makefile b/tools/kvm/Makefile
index 4f0b26199bcb..9d6564c82455 100644
--- a/tools/kvm/Makefile
+++ b/tools/kvm/Makefile
@@ -11,6 +11,7 @@ PROGRAM	= kvm
 
 OBJS	+= blk-virtio.o
 OBJS	+= cpuid.o
+OBJS	+= disk-image.o
 OBJS	+= early_printk.o
 OBJS	+= interrupt.o
 OBJS	+= ioport.o
diff --git a/tools/kvm/disk-image.c b/tools/kvm/disk-image.c
new file mode 100644
index 000000000000..92aa83f68ce5
--- /dev/null
+++ b/tools/kvm/disk-image.c
@@ -0,0 +1,69 @@
+#include "kvm/disk-image.h"
+
+#include "kvm/util.h"
+
+#include <sys/types.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+#define SECTOR_SHIFT		9
+#define SECTOR_SIZE		(1UL << SECTOR_SHIFT)
+
+struct disk_image *disk_image__open(const char *filename)
+{
+	struct disk_image *self;
+	struct stat st;
+
+	self		= malloc(sizeof *self);
+	if (!self)
+		return NULL;
+
+	self->fd	= open(filename, O_RDONLY);
+	if (self->fd < 0)
+		goto failed_free;
+
+	if (fstat(self->fd, &st) < 0)
+		goto failed_close_fd;
+
+	self->size	= st.st_size;
+
+	self->mmap	= mmap(NULL, self->size, PROT_READ, MAP_PRIVATE, self->fd, 0);
+	if (self->mmap == MAP_FAILED)
+		goto failed_close_fd;
+
+	return self;
+
+failed_close_fd:
+	close(self->fd);
+failed_free:
+	free(self);
+
+	return NULL;
+}
+
+void disk_image__close(struct disk_image *self)
+{
+	if (munmap(self->mmap, self->size) < 0)
+		warning("munmap() failed");
+
+	if (close(self->fd) < 0)
+		warning("close() failed");
+
+	free(self);
+}
+
+int disk_image__read_sector(struct disk_image *self, uint64_t sector, void *dst)
+{
+	uint64_t offset = sector << SECTOR_SHIFT;
+
+	if (offset + SECTOR_SIZE > self->size)
+		return -1;
+
+	memcpy(dst, self->mmap + offset, SECTOR_SIZE);
+
+	return 0;
+}
diff --git a/tools/kvm/include/kvm/disk-image.h b/tools/kvm/include/kvm/disk-image.h
new file mode 100644
index 000000000000..a7698f1d632f
--- /dev/null
+++ b/tools/kvm/include/kvm/disk-image.h
@@ -0,0 +1,16 @@
+#ifndef KVM__DISK_IMAGE_H
+#define KVM__DISK_IMAGE_H
+
+#include <stdint.h>
+
+struct disk_image {
+	void		*mmap;
+	int		fd;
+	uint64_t	size;
+};
+
+struct disk_image *disk_image__open(const char *filename);
+void disk_image__close(struct disk_image *self);
+int disk_image__read_sector(struct disk_image *self, uint64_t sector, void *dst);
+
+#endif /* KVM__DISK_IMAGE_H */
diff --git a/tools/kvm/include/kvm/kvm.h b/tools/kvm/include/kvm/kvm.h
index 9cf2f73a7d19..48f837306dc0 100644
--- a/tools/kvm/include/kvm/kvm.h
+++ b/tools/kvm/include/kvm/kvm.h
@@ -14,6 +14,7 @@ struct kvm {
 	int			vcpu_fd;	/* For VCPU ioctls() */
 	struct kvm_run		*kvm_run;
 
+	struct disk_image	*disk_image;
 	uint64_t		ram_size;
 	void			*ram_start;
 
diff --git a/tools/kvm/main.c b/tools/kvm/main.c
index c12d3d0ad5a0..89c194e17165 100644
--- a/tools/kvm/main.c
+++ b/tools/kvm/main.c
@@ -2,6 +2,7 @@
 
 #include "kvm/early_printk.h"
 #include "kvm/blk-virtio.h"
+#include "kvm/disk-image.h"
 #include "kvm/util.h"
 #include "kvm/pci.h"
 
@@ -19,7 +20,7 @@ static void usage(char *argv[])
 	fprintf(stderr, "  usage: %s "
 		"[--single-step] [--ioport-debug] "
 		"[--kvm-dev=<device>] [--mem=<size-in-MiB>] [--params=<kernel-params>] "
-		"[--initrd=<initrd>] [--kernel=]<kernel-image>\n",
+		"[--initrd=<initrd>] [--kernel=]<kernel-image> [--image=]<disk-image>\n",
 		argv[0]);
 	exit(1);
 }
@@ -48,6 +49,7 @@ int main(int argc, char *argv[])
 {
 	const char *kernel_filename = NULL;
 	const char *initrd_filename = NULL;
+	const char *image_filename = NULL;
 	const char *kernel_cmdline = NULL;
 	const char *kvm_dev = "/dev/kvm";
 	unsigned long ram_size = 64UL << 20;
@@ -61,6 +63,9 @@ int main(int argc, char *argv[])
 		if (option_matches(argv[i], "--kernel=")) {
 			kernel_filename	= &argv[i][9];
 			continue;
+		} else if (option_matches(argv[i], "--image=")) {
+			image_filename	= &argv[i][8];
+			continue;
 		} else if (option_matches(argv[i], "--initrd=")) {
 			initrd_filename	= &argv[i][9];
 			continue;
@@ -101,6 +106,12 @@ int main(int argc, char *argv[])
 
 	kvm = kvm__init(kvm_dev, ram_size);
 
+	if (image_filename) {
+		kvm->disk_image	= disk_image__open(image_filename);
+		if (!kvm->disk_image)
+			die("unable to load disk image %s", image_filename);
+	}
+
 	kvm__setup_cpuid(kvm);
 
 	strcpy(real_cmdline, "notsc nolapic nosmp noacpi pci=conf1 earlyprintk=ttyS0,keep ");