All of lore.kernel.org
 help / color / mirror / Atom feed
* [kvmtool][PATCH v2] arm64: Obtain text offset from kernel image
@ 2020-06-08 15:28 ` Marc Zyngier
  0 siblings, 0 replies; 6+ messages in thread
From: Marc Zyngier @ 2020-06-08 15:28 UTC (permalink / raw)
  To: kvmarm, linux-arm-kernel; +Cc: Will Deacon, Ard Biesheuvel

Recent changes made to Linux 5.8 have outlined that kvmtool
hardcodes the text offset instead of reading it from the arm64
image itself.

To address this, import the image header structure into kvmtool
and do the right thing. 32bit guests are still loaded to their
usual locations.

While we're at it, check the image magic and default to the text
offset to be 0x80000 when image_size is 0, as described in the
kernel's booting.rst document.

Cc: Alexandru Elisei <alexandru.elisei@arm.com>
Reported-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
---

Notes:
    v2: Check magic, assume offset to be 0x8000 if image_size is 0.

 Makefile                           |  1 +
 arm/aarch32/include/kvm/kvm-arch.h |  2 +-
 arm/aarch64/include/asm/image.h    | 59 ++++++++++++++++++++++++++++++
 arm/aarch64/include/kvm/kvm-arch.h |  5 +--
 arm/aarch64/kvm.c                  | 43 ++++++++++++++++++++++
 arm/kvm.c                          |  2 +-
 6 files changed, 107 insertions(+), 5 deletions(-)
 create mode 100644 arm/aarch64/include/asm/image.h
 create mode 100644 arm/aarch64/kvm.c

diff --git a/Makefile b/Makefile
index d27ff38..35bb118 100644
--- a/Makefile
+++ b/Makefile
@@ -179,6 +179,7 @@ ifeq ($(ARCH), arm64)
 	OBJS		+= $(OBJS_ARM_COMMON)
 	OBJS		+= arm/aarch64/arm-cpu.o
 	OBJS		+= arm/aarch64/kvm-cpu.o
+	OBJS		+= arm/aarch64/kvm.o
 	ARCH_INCLUDE	:= $(HDRS_ARM_COMMON)
 	ARCH_INCLUDE	+= -Iarm/aarch64/include
 
diff --git a/arm/aarch32/include/kvm/kvm-arch.h b/arm/aarch32/include/kvm/kvm-arch.h
index cd31e72..a772bb1 100644
--- a/arm/aarch32/include/kvm/kvm-arch.h
+++ b/arm/aarch32/include/kvm/kvm-arch.h
@@ -1,7 +1,7 @@
 #ifndef KVM__KVM_ARCH_H
 #define KVM__KVM_ARCH_H
 
-#define ARM_KERN_OFFSET(...)	0x8000
+#define kvm__arch_get_kern_offset(...)	0x8000
 
 #define ARM_MAX_MEMORY(...)	ARM_LOMAP_MAX_MEMORY
 
diff --git a/arm/aarch64/include/asm/image.h b/arm/aarch64/include/asm/image.h
new file mode 100644
index 0000000..c2b1321
--- /dev/null
+++ b/arm/aarch64/include/asm/image.h
@@ -0,0 +1,59 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __ASM_IMAGE_H
+#define __ASM_IMAGE_H
+
+#define ARM64_IMAGE_MAGIC	"ARM\x64"
+
+#define ARM64_IMAGE_FLAG_BE_SHIFT		0
+#define ARM64_IMAGE_FLAG_PAGE_SIZE_SHIFT	(ARM64_IMAGE_FLAG_BE_SHIFT + 1)
+#define ARM64_IMAGE_FLAG_PHYS_BASE_SHIFT \
+					(ARM64_IMAGE_FLAG_PAGE_SIZE_SHIFT + 2)
+#define ARM64_IMAGE_FLAG_BE_MASK		0x1
+#define ARM64_IMAGE_FLAG_PAGE_SIZE_MASK		0x3
+#define ARM64_IMAGE_FLAG_PHYS_BASE_MASK		0x1
+
+#define ARM64_IMAGE_FLAG_LE			0
+#define ARM64_IMAGE_FLAG_BE			1
+#define ARM64_IMAGE_FLAG_PAGE_SIZE_4K		1
+#define ARM64_IMAGE_FLAG_PAGE_SIZE_16K		2
+#define ARM64_IMAGE_FLAG_PAGE_SIZE_64K		3
+#define ARM64_IMAGE_FLAG_PHYS_BASE		1
+
+#ifndef __ASSEMBLY__
+
+#define arm64_image_flag_field(flags, field) \
+				(((flags) >> field##_SHIFT) & field##_MASK)
+
+/*
+ * struct arm64_image_header - arm64 kernel image header
+ * See Documentation/arm64/booting.rst for details
+ *
+ * @code0:		Executable code, or
+ *   @mz_header		  alternatively used for part of MZ header
+ * @code1:		Executable code
+ * @text_offset:	Image load offset
+ * @image_size:		Effective Image size
+ * @flags:		kernel flags
+ * @reserved:		reserved
+ * @magic:		Magic number
+ * @reserved5:		reserved, or
+ *   @pe_header:	  alternatively used for PE COFF offset
+ */
+
+struct arm64_image_header {
+	__le32 code0;
+	__le32 code1;
+	__le64 text_offset;
+	__le64 image_size;
+	__le64 flags;
+	__le64 res2;
+	__le64 res3;
+	__le64 res4;
+	__le32 magic;
+	__le32 res5;
+};
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* __ASM_IMAGE_H */
diff --git a/arm/aarch64/include/kvm/kvm-arch.h b/arm/aarch64/include/kvm/kvm-arch.h
index 9de623a..55ef8ed 100644
--- a/arm/aarch64/include/kvm/kvm-arch.h
+++ b/arm/aarch64/include/kvm/kvm-arch.h
@@ -1,9 +1,8 @@
 #ifndef KVM__KVM_ARCH_H
 #define KVM__KVM_ARCH_H
 
-#define ARM_KERN_OFFSET(kvm)	((kvm)->cfg.arch.aarch32_guest	?	\
-				0x8000				:	\
-				0x80000)
+struct kvm;
+unsigned long long kvm__arch_get_kern_offset(struct kvm *kvm, int fd);
 
 #define ARM_MAX_MEMORY(kvm)	((kvm)->cfg.arch.aarch32_guest	?	\
 				ARM_LOMAP_MAX_MEMORY		:	\
diff --git a/arm/aarch64/kvm.c b/arm/aarch64/kvm.c
new file mode 100644
index 0000000..a46d438
--- /dev/null
+++ b/arm/aarch64/kvm.c
@@ -0,0 +1,43 @@
+#include "kvm/kvm.h"
+
+#include <asm/image.h>
+
+#include <linux/byteorder.h>
+
+/*
+ * Return the TEXT_OFFSET value that the guest kernel expects. Note
+ * that pre-3.17 kernels expose this value using the native endianness
+ * instead of Little-Endian. BE kernels of this vintage may fail to
+ * boot. See Documentation/arm64/booting.rst in your local kernel tree.
+ */
+unsigned long long kvm__arch_get_kern_offset(struct kvm *kvm, int fd)
+{
+	struct arm64_image_header header;
+	off_t cur_offset;
+	ssize_t size;
+
+	/* the 32bit kernel offset is a well known value */
+	if (kvm->cfg.arch.aarch32_guest)
+		return 0x8000;
+
+	cur_offset = lseek(fd, 0, SEEK_CUR);
+	if (cur_offset == (off_t)-1 ||
+	    lseek(fd, 0, SEEK_SET) == (off_t)-1)
+		die("Failed to seek in image file");
+
+	size = xread(fd, &header, sizeof(header));
+	if (size < 0 || (size_t)size < sizeof(header))
+		die("Failed to read kernel image header");
+
+	lseek(fd, cur_offset, SEEK_SET);
+
+	if (memcmp(&header.magic, ARM64_IMAGE_MAGIC, sizeof(header.magic)))
+		pr_warning("Kernel image magic not matching");
+
+	if (le64_to_cpu(header.image_size))
+		return le64_to_cpu(header.text_offset);
+
+	pr_warning("Image size is 0, assuming TEXT_OFFSET to be 0x80000");
+	return 0x80000;
+}
+
diff --git a/arm/kvm.c b/arm/kvm.c
index 1f85fc6..5aea18f 100644
--- a/arm/kvm.c
+++ b/arm/kvm.c
@@ -103,7 +103,7 @@ bool kvm__arch_load_kernel_image(struct kvm *kvm, int fd_kernel, int fd_initrd,
 	 */
 	limit = kvm->ram_start + min(kvm->ram_size, (u64)SZ_256M) - 1;
 
-	pos = kvm->ram_start + ARM_KERN_OFFSET(kvm);
+	pos = kvm->ram_start + kvm__arch_get_kern_offset(kvm, fd_kernel);
 	kvm->arch.kern_guest_start = host_to_guest_flat(kvm, pos);
 	file_size = read_file(fd_kernel, pos, limit - pos);
 	if (file_size < 0) {
-- 
2.26.2

_______________________________________________
kvmarm mailing list
kvmarm@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm

^ permalink raw reply related	[flat|nested] 6+ messages in thread
* [kvmtool][PATCH v2] arm64: Obtain text offset from kernel image
@ 2020-06-08 15:28 ` Marc Zyngier
  0 siblings, 0 replies; 6+ messages in thread
From: Marc Zyngier @ 2020-06-08 15:28 UTC (permalink / raw)
  To: kvmarm, linux-arm-kernel
  Cc: Alexandru Elisei, Will Deacon, Ard Biesheuvel, Julien Thierry

Recent changes made to Linux 5.8 have outlined that kvmtool
hardcodes the text offset instead of reading it from the arm64
image itself.

To address this, import the image header structure into kvmtool
and do the right thing. 32bit guests are still loaded to their
usual locations.

While we're at it, check the image magic and default to the text
offset to be 0x80000 when image_size is 0, as described in the
kernel's booting.rst document.

Cc: Alexandru Elisei <alexandru.elisei@arm.com>
Reported-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
---

Notes:
    v2: Check magic, assume offset to be 0x8000 if image_size is 0.

 Makefile                           |  1 +
 arm/aarch32/include/kvm/kvm-arch.h |  2 +-
 arm/aarch64/include/asm/image.h    | 59 ++++++++++++++++++++++++++++++
 arm/aarch64/include/kvm/kvm-arch.h |  5 +--
 arm/aarch64/kvm.c                  | 43 ++++++++++++++++++++++
 arm/kvm.c                          |  2 +-
 6 files changed, 107 insertions(+), 5 deletions(-)
 create mode 100644 arm/aarch64/include/asm/image.h
 create mode 100644 arm/aarch64/kvm.c

diff --git a/Makefile b/Makefile
index d27ff38..35bb118 100644
--- a/Makefile
+++ b/Makefile
@@ -179,6 +179,7 @@ ifeq ($(ARCH), arm64)
 	OBJS		+= $(OBJS_ARM_COMMON)
 	OBJS		+= arm/aarch64/arm-cpu.o
 	OBJS		+= arm/aarch64/kvm-cpu.o
+	OBJS		+= arm/aarch64/kvm.o
 	ARCH_INCLUDE	:= $(HDRS_ARM_COMMON)
 	ARCH_INCLUDE	+= -Iarm/aarch64/include
 
diff --git a/arm/aarch32/include/kvm/kvm-arch.h b/arm/aarch32/include/kvm/kvm-arch.h
index cd31e72..a772bb1 100644
--- a/arm/aarch32/include/kvm/kvm-arch.h
+++ b/arm/aarch32/include/kvm/kvm-arch.h
@@ -1,7 +1,7 @@
 #ifndef KVM__KVM_ARCH_H
 #define KVM__KVM_ARCH_H
 
-#define ARM_KERN_OFFSET(...)	0x8000
+#define kvm__arch_get_kern_offset(...)	0x8000
 
 #define ARM_MAX_MEMORY(...)	ARM_LOMAP_MAX_MEMORY
 
diff --git a/arm/aarch64/include/asm/image.h b/arm/aarch64/include/asm/image.h
new file mode 100644
index 0000000..c2b1321
--- /dev/null
+++ b/arm/aarch64/include/asm/image.h
@@ -0,0 +1,59 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __ASM_IMAGE_H
+#define __ASM_IMAGE_H
+
+#define ARM64_IMAGE_MAGIC	"ARM\x64"
+
+#define ARM64_IMAGE_FLAG_BE_SHIFT		0
+#define ARM64_IMAGE_FLAG_PAGE_SIZE_SHIFT	(ARM64_IMAGE_FLAG_BE_SHIFT + 1)
+#define ARM64_IMAGE_FLAG_PHYS_BASE_SHIFT \
+					(ARM64_IMAGE_FLAG_PAGE_SIZE_SHIFT + 2)
+#define ARM64_IMAGE_FLAG_BE_MASK		0x1
+#define ARM64_IMAGE_FLAG_PAGE_SIZE_MASK		0x3
+#define ARM64_IMAGE_FLAG_PHYS_BASE_MASK		0x1
+
+#define ARM64_IMAGE_FLAG_LE			0
+#define ARM64_IMAGE_FLAG_BE			1
+#define ARM64_IMAGE_FLAG_PAGE_SIZE_4K		1
+#define ARM64_IMAGE_FLAG_PAGE_SIZE_16K		2
+#define ARM64_IMAGE_FLAG_PAGE_SIZE_64K		3
+#define ARM64_IMAGE_FLAG_PHYS_BASE		1
+
+#ifndef __ASSEMBLY__
+
+#define arm64_image_flag_field(flags, field) \
+				(((flags) >> field##_SHIFT) & field##_MASK)
+
+/*
+ * struct arm64_image_header - arm64 kernel image header
+ * See Documentation/arm64/booting.rst for details
+ *
+ * @code0:		Executable code, or
+ *   @mz_header		  alternatively used for part of MZ header
+ * @code1:		Executable code
+ * @text_offset:	Image load offset
+ * @image_size:		Effective Image size
+ * @flags:		kernel flags
+ * @reserved:		reserved
+ * @magic:		Magic number
+ * @reserved5:		reserved, or
+ *   @pe_header:	  alternatively used for PE COFF offset
+ */
+
+struct arm64_image_header {
+	__le32 code0;
+	__le32 code1;
+	__le64 text_offset;
+	__le64 image_size;
+	__le64 flags;
+	__le64 res2;
+	__le64 res3;
+	__le64 res4;
+	__le32 magic;
+	__le32 res5;
+};
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* __ASM_IMAGE_H */
diff --git a/arm/aarch64/include/kvm/kvm-arch.h b/arm/aarch64/include/kvm/kvm-arch.h
index 9de623a..55ef8ed 100644
--- a/arm/aarch64/include/kvm/kvm-arch.h
+++ b/arm/aarch64/include/kvm/kvm-arch.h
@@ -1,9 +1,8 @@
 #ifndef KVM__KVM_ARCH_H
 #define KVM__KVM_ARCH_H
 
-#define ARM_KERN_OFFSET(kvm)	((kvm)->cfg.arch.aarch32_guest	?	\
-				0x8000				:	\
-				0x80000)
+struct kvm;
+unsigned long long kvm__arch_get_kern_offset(struct kvm *kvm, int fd);
 
 #define ARM_MAX_MEMORY(kvm)	((kvm)->cfg.arch.aarch32_guest	?	\
 				ARM_LOMAP_MAX_MEMORY		:	\
diff --git a/arm/aarch64/kvm.c b/arm/aarch64/kvm.c
new file mode 100644
index 0000000..a46d438
--- /dev/null
+++ b/arm/aarch64/kvm.c
@@ -0,0 +1,43 @@
+#include "kvm/kvm.h"
+
+#include <asm/image.h>
+
+#include <linux/byteorder.h>
+
+/*
+ * Return the TEXT_OFFSET value that the guest kernel expects. Note
+ * that pre-3.17 kernels expose this value using the native endianness
+ * instead of Little-Endian. BE kernels of this vintage may fail to
+ * boot. See Documentation/arm64/booting.rst in your local kernel tree.
+ */
+unsigned long long kvm__arch_get_kern_offset(struct kvm *kvm, int fd)
+{
+	struct arm64_image_header header;
+	off_t cur_offset;
+	ssize_t size;
+
+	/* the 32bit kernel offset is a well known value */
+	if (kvm->cfg.arch.aarch32_guest)
+		return 0x8000;
+
+	cur_offset = lseek(fd, 0, SEEK_CUR);
+	if (cur_offset == (off_t)-1 ||
+	    lseek(fd, 0, SEEK_SET) == (off_t)-1)
+		die("Failed to seek in image file");
+
+	size = xread(fd, &header, sizeof(header));
+	if (size < 0 || (size_t)size < sizeof(header))
+		die("Failed to read kernel image header");
+
+	lseek(fd, cur_offset, SEEK_SET);
+
+	if (memcmp(&header.magic, ARM64_IMAGE_MAGIC, sizeof(header.magic)))
+		pr_warning("Kernel image magic not matching");
+
+	if (le64_to_cpu(header.image_size))
+		return le64_to_cpu(header.text_offset);
+
+	pr_warning("Image size is 0, assuming TEXT_OFFSET to be 0x80000");
+	return 0x80000;
+}
+
diff --git a/arm/kvm.c b/arm/kvm.c
index 1f85fc6..5aea18f 100644
--- a/arm/kvm.c
+++ b/arm/kvm.c
@@ -103,7 +103,7 @@ bool kvm__arch_load_kernel_image(struct kvm *kvm, int fd_kernel, int fd_initrd,
 	 */
 	limit = kvm->ram_start + min(kvm->ram_size, (u64)SZ_256M) - 1;
 
-	pos = kvm->ram_start + ARM_KERN_OFFSET(kvm);
+	pos = kvm->ram_start + kvm__arch_get_kern_offset(kvm, fd_kernel);
 	kvm->arch.kern_guest_start = host_to_guest_flat(kvm, pos);
 	file_size = read_file(fd_kernel, pos, limit - pos);
 	if (file_size < 0) {
-- 
2.26.2


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply related	[flat|nested] 6+ messages in thread
* Re: [PATCH v2] arm64: Obtain text offset from kernel image
  2020-06-08 15:28 ` Marc Zyngier
@ 2020-06-08 15:37   ` Will Deacon
  -1 siblings, 0 replies; 6+ messages in thread
From: Will Deacon @ 2020-06-08 15:37 UTC (permalink / raw)
  To: kvmarm, Marc Zyngier, linux-arm-kernel
  Cc: catalin.marinas, Will Deacon, Ard Biesheuvel

On Mon, 8 Jun 2020 16:28:01 +0100, Marc Zyngier wrote:
> Recent changes made to Linux 5.8 have outlined that kvmtool
> hardcodes the text offset instead of reading it from the arm64
> image itself.
> 
> To address this, import the image header structure into kvmtool
> and do the right thing. 32bit guests are still loaded to their
> usual locations.
> 
> [...]

Applied to kvmtool (master), thanks!

[1/1] arm64: Obtain text offset from kernel image
      https://git.kernel.org/will/kvmtool/c/fd0a05bd27dd

Cheers,
-- 
Will

https://fixes.arm64.dev
https://next.arm64.dev
https://will.arm64.dev
_______________________________________________
kvmarm mailing list
kvmarm@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm

^ permalink raw reply	[flat|nested] 6+ messages in thread
* Re: [PATCH v2] arm64: Obtain text offset from kernel image
@ 2020-06-08 15:37   ` Will Deacon
  0 siblings, 0 replies; 6+ messages in thread
From: Will Deacon @ 2020-06-08 15:37 UTC (permalink / raw)
  To: kvmarm, Marc Zyngier, linux-arm-kernel
  Cc: catalin.marinas, Will Deacon, Ard Biesheuvel

On Mon, 8 Jun 2020 16:28:01 +0100, Marc Zyngier wrote:
> Recent changes made to Linux 5.8 have outlined that kvmtool
> hardcodes the text offset instead of reading it from the arm64
> image itself.
> 
> To address this, import the image header structure into kvmtool
> and do the right thing. 32bit guests are still loaded to their
> usual locations.
> 
> [...]

Applied to kvmtool (master), thanks!

[1/1] arm64: Obtain text offset from kernel image
      https://git.kernel.org/will/kvmtool/c/fd0a05bd27dd

Cheers,
-- 
Will

https://fixes.arm64.dev
https://next.arm64.dev
https://will.arm64.dev

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 6+ messages in thread
* Re: [kvmtool][PATCH v2] arm64: Obtain text offset from kernel image
  2020-06-08 15:28 ` Marc Zyngier
@ 2020-06-09 10:08   ` Alexandru Elisei
  -1 siblings, 0 replies; 6+ messages in thread
From: Alexandru Elisei @ 2020-06-09 10:08 UTC (permalink / raw)
  To: Marc Zyngier, kvmarm, linux-arm-kernel; +Cc: Will Deacon, Ard Biesheuvel

Hi,

On 6/8/20 4:28 PM, Marc Zyngier wrote:
> Recent changes made to Linux 5.8 have outlined that kvmtool
> hardcodes the text offset instead of reading it from the arm64
> image itself.
>
> To address this, import the image header structure into kvmtool
> and do the right thing. 32bit guests are still loaded to their
> usual locations.
>
> While we're at it, check the image magic and default to the text
> offset to be 0x80000 when image_size is 0, as described in the
> kernel's booting.rst document.
>
> Cc: Alexandru Elisei <alexandru.elisei@arm.com>
> Reported-by: Ard Biesheuvel <ardb@kernel.org>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> ---
>
> Notes:
>     v2: Check magic, assume offset to be 0x8000 if image_size is 0.
>
> [..]

I wanted to review the patch, but then I noticed that Will merged it. So I settled
for testing it, to make sure nothing breaks. I was able to reproduce the issue
reported on the mailing list - without this patch, when the kernel is compiled
with CONFIG_RANDOMIZE_BASE not set, the kernel doesn't boot; with this patch
applied, the same kernel boots successfully.

I also tested it with an aarch32 kernel, this is what I got:

$ taskset -c 4,5 ./lkvm run -c2 -m1024 -k ../kvmtool-vms/zImage -d
../kvmtool-vms/debian-10.3.0.img  -p 'earlycon root=/dev/vda2'
  # lkvm run -k ../kvmtool-vms/zImage -m 1024 -c 2 --name guest-1834
  Warning: Kernel image magic not matching
  Warning: unable to translate host address 0x13115a4c82d05a4d to guest
  Fatal: kernel image too big to contain in guest memory.

IMO, works as expected.

Thanks,
Alex
_______________________________________________
kvmarm mailing list
kvmarm@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm

^ permalink raw reply	[flat|nested] 6+ messages in thread
* Re: [kvmtool][PATCH v2] arm64: Obtain text offset from kernel image
@ 2020-06-09 10:08   ` Alexandru Elisei
  0 siblings, 0 replies; 6+ messages in thread
From: Alexandru Elisei @ 2020-06-09 10:08 UTC (permalink / raw)
  To: Marc Zyngier, kvmarm, linux-arm-kernel
  Cc: Will Deacon, Ard Biesheuvel, Julien Thierry

Hi,

On 6/8/20 4:28 PM, Marc Zyngier wrote:
> Recent changes made to Linux 5.8 have outlined that kvmtool
> hardcodes the text offset instead of reading it from the arm64
> image itself.
>
> To address this, import the image header structure into kvmtool
> and do the right thing. 32bit guests are still loaded to their
> usual locations.
>
> While we're at it, check the image magic and default to the text
> offset to be 0x80000 when image_size is 0, as described in the
> kernel's booting.rst document.
>
> Cc: Alexandru Elisei <alexandru.elisei@arm.com>
> Reported-by: Ard Biesheuvel <ardb@kernel.org>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> ---
>
> Notes:
>     v2: Check magic, assume offset to be 0x8000 if image_size is 0.
>
> [..]

I wanted to review the patch, but then I noticed that Will merged it. So I settled
for testing it, to make sure nothing breaks. I was able to reproduce the issue
reported on the mailing list - without this patch, when the kernel is compiled
with CONFIG_RANDOMIZE_BASE not set, the kernel doesn't boot; with this patch
applied, the same kernel boots successfully.

I also tested it with an aarch32 kernel, this is what I got:

$ taskset -c 4,5 ./lkvm run -c2 -m1024 -k ../kvmtool-vms/zImage -d
../kvmtool-vms/debian-10.3.0.img  -p 'earlycon root=/dev/vda2'
  # lkvm run -k ../kvmtool-vms/zImage -m 1024 -c 2 --name guest-1834
  Warning: Kernel image magic not matching
  Warning: unable to translate host address 0x13115a4c82d05a4d to guest
  Fatal: kernel image too big to contain in guest memory.

IMO, works as expected.

Thanks,
Alex

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 6+ messages in thread
end of thread, other threads:[~2020-06-09 10:08 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-06-08 15:28 [kvmtool][PATCH v2] arm64: Obtain text offset from kernel image Marc Zyngier
2020-06-08 15:28 ` Marc Zyngier
2020-06-08 15:37 ` [PATCH " Will Deacon
2020-06-08 15:37   ` Will Deacon
2020-06-09 10:08 ` [kvmtool][PATCH " Alexandru Elisei
2020-06-09 10:08   ` Alexandru Elisei

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.