[PATCH 2/9] kexec: add public interface for improved load/unload sub-ops
Don Slutz
dslutz at verizon.com
Thu Nov 7 15:38:17 EST 2013
For what it is worth.
Reviewed-by: Don Slutz <dslutz at verizon.com>
-Don Slutz
On 11/06/13 09:49, David Vrabel wrote:
> From: David Vrabel <david.vrabel at citrix.com>
>
> Add replacement KEXEC_CMD_load and KEXEC_CMD_unload sub-ops to the
> kexec hypercall. These new sub-ops allow a priviledged guest to
> provide the image data to be loaded into Xen memory or the crash
> region instead of guests loading the image data themselves and
> providing the relocation code and metadata.
>
> The old interface is provided to guests requesting an interface
> version prior to 4.4.
>
> Bump __XEN_LATEST_INTERFACE_VERSION__ to 0x00040400.
>
> Signed-off: David Vrabel <david.vrabel at citrix.com>
> Reviewed-by: Andrew Cooper <andrew.cooper3 at citrix.com>
> ---
> xen/common/kexec.c | 12 +++---
> xen/include/public/kexec.h | 92 +++++++++++++++++++++++++++++++++++++--
> xen/include/public/xen-compat.h | 2 +-
> 3 files changed, 95 insertions(+), 11 deletions(-)
>
> diff --git a/xen/common/kexec.c b/xen/common/kexec.c
> index 7cd151f..7b23df0 100644
> --- a/xen/common/kexec.c
> +++ b/xen/common/kexec.c
> @@ -734,7 +734,7 @@ static void crash_save_vmcoreinfo(void)
> #endif
> }
>
> -static int kexec_load_unload_internal(unsigned long op, xen_kexec_load_t *load)
> +static int kexec_load_unload_internal(unsigned long op, xen_kexec_load_v1_t *load)
> {
> xen_kexec_image_t *image;
> int base, bit, pos;
> @@ -781,7 +781,7 @@ static int kexec_load_unload_internal(unsigned long op, xen_kexec_load_t *load)
>
> static int kexec_load_unload(unsigned long op, XEN_GUEST_HANDLE_PARAM(void) uarg)
> {
> - xen_kexec_load_t load;
> + xen_kexec_load_v1_t load;
>
> if ( unlikely(copy_from_guest(&load, uarg, 1)) )
> return -EFAULT;
> @@ -793,8 +793,8 @@ static int kexec_load_unload_compat(unsigned long op,
> XEN_GUEST_HANDLE_PARAM(void) uarg)
> {
> #ifdef CONFIG_COMPAT
> - compat_kexec_load_t compat_load;
> - xen_kexec_load_t load;
> + compat_kexec_load_v1_t compat_load;
> + xen_kexec_load_v1_t load;
>
> if ( unlikely(copy_from_guest(&compat_load, uarg, 1)) )
> return -EFAULT;
> @@ -866,8 +866,8 @@ static int do_kexec_op_internal(unsigned long op,
> else
> ret = kexec_get_range(uarg);
> break;
> - case KEXEC_CMD_kexec_load:
> - case KEXEC_CMD_kexec_unload:
> + case KEXEC_CMD_kexec_load_v1:
> + case KEXEC_CMD_kexec_unload_v1:
> spin_lock_irqsave(&kexec_lock, flags);
> if (!test_bit(KEXEC_FLAG_IN_PROGRESS, &kexec_flags))
> {
> diff --git a/xen/include/public/kexec.h b/xen/include/public/kexec.h
> index 36409ff..a6a0a88 100644
> --- a/xen/include/public/kexec.h
> +++ b/xen/include/public/kexec.h
> @@ -105,6 +105,20 @@ typedef struct xen_kexec_image {
> * Perform kexec having previously loaded a kexec or kdump kernel
> * as appropriate.
> * type == KEXEC_TYPE_DEFAULT or KEXEC_TYPE_CRASH [in]
> + *
> + * Control is transferred to the image entry point with the host in
> + * the following state.
> + *
> + * - The image may be executed on any PCPU and all other PCPUs are
> + * stopped.
> + *
> + * - Local interrupts are disabled.
> + *
> + * - Register values are undefined.
> + *
> + * - The image segments have writeable 1:1 virtual to machine
> + * mappings. The location of any page tables is undefined and these
> + * page table frames are not be mapped.
> */
> #define KEXEC_CMD_kexec 0
> typedef struct xen_kexec_exec {
> @@ -116,12 +130,12 @@ typedef struct xen_kexec_exec {
> * type == KEXEC_TYPE_DEFAULT or KEXEC_TYPE_CRASH [in]
> * image == relocation information for kexec (ignored for unload) [in]
> */
> -#define KEXEC_CMD_kexec_load 1
> -#define KEXEC_CMD_kexec_unload 2
> -typedef struct xen_kexec_load {
> +#define KEXEC_CMD_kexec_load_v1 1 /* obsolete since 0x00040400 */
> +#define KEXEC_CMD_kexec_unload_v1 2 /* obsolete since 0x00040400 */
> +typedef struct xen_kexec_load_v1 {
> int type;
> xen_kexec_image_t image;
> -} xen_kexec_load_t;
> +} xen_kexec_load_v1_t;
>
> #define KEXEC_RANGE_MA_CRASH 0 /* machine address and size of crash area */
> #define KEXEC_RANGE_MA_XEN 1 /* machine address and size of Xen itself */
> @@ -152,6 +166,76 @@ typedef struct xen_kexec_range {
> unsigned long start;
> } xen_kexec_range_t;
>
> +#if __XEN_INTERFACE_VERSION__ >= 0x00040400
> +/*
> + * A contiguous chunk of a kexec image and it's destination machine
> + * address.
> + */
> +typedef struct xen_kexec_segment {
> + union {
> + XEN_GUEST_HANDLE(const_void) h;
> + uint64_t _pad;
> + } buf;
> + uint64_t buf_size;
> + uint64_t dest_maddr;
> + uint64_t dest_size;
> +} xen_kexec_segment_t;
> +DEFINE_XEN_GUEST_HANDLE(xen_kexec_segment_t);
> +
> +/*
> + * Load a kexec image into memory.
> + *
> + * For KEXEC_TYPE_DEFAULT images, the segments may be anywhere in RAM.
> + * The image is relocated prior to being executed.
> + *
> + * For KEXEC_TYPE_CRASH images, each segment of the image must reside
> + * in the memory region reserved for kexec (KEXEC_RANGE_MA_CRASH) and
> + * the entry point must be within the image. The caller is responsible
> + * for ensuring that multiple images do not overlap.
> + *
> + * All image segments will be loaded to their destination machine
> + * addresses prior to being executed. The trailing portion of any
> + * segments with a source buffer (from dest_maddr + buf_size to
> + * dest_maddr + dest_size) will be zeroed.
> + *
> + * Segments with no source buffer will be accessible to the image when
> + * it is executed.
> + */
> +
> +#define KEXEC_CMD_kexec_load 4
> +typedef struct xen_kexec_load {
> + uint8_t type; /* One of KEXEC_TYPE_* */
> + uint8_t _pad;
> + uint16_t arch; /* ELF machine type (EM_*). */
> + uint32_t nr_segments;
> + union {
> + XEN_GUEST_HANDLE(xen_kexec_segment_t) h;
> + uint64_t _pad;
> + } segments;
> + uint64_t entry_maddr; /* image entry point machine address. */
> +} xen_kexec_load_t;
> +DEFINE_XEN_GUEST_HANDLE(xen_kexec_load_t);
> +
> +/*
> + * Unload a kexec image.
> + *
> + * Type must be one of KEXEC_TYPE_DEFAULT or KEXEC_TYPE_CRASH.
> + */
> +#define KEXEC_CMD_kexec_unload 5
> +typedef struct xen_kexec_unload {
> + uint8_t type;
> +} xen_kexec_unload_t;
> +DEFINE_XEN_GUEST_HANDLE(xen_kexec_unload_t);
> +
> +#else /* __XEN_INTERFACE_VERSION__ < 0x00040400 */
> +
> +#define KEXEC_CMD_kexec_load KEXEC_CMD_kexec_load_v1
> +#define KEXEC_CMD_kexec_unload KEXEC_CMD_kexec_unload_v1
> +#define xen_kexec_load xen_kexec_load_v1
> +#define xen_kexec_load_t xen_kexec_load_v1_t
> +
> +#endif
> +
> #endif /* _XEN_PUBLIC_KEXEC_H */
>
> /*
> diff --git a/xen/include/public/xen-compat.h b/xen/include/public/xen-compat.h
> index 69141c4..3eb80a0 100644
> --- a/xen/include/public/xen-compat.h
> +++ b/xen/include/public/xen-compat.h
> @@ -27,7 +27,7 @@
> #ifndef __XEN_PUBLIC_XEN_COMPAT_H__
> #define __XEN_PUBLIC_XEN_COMPAT_H__
>
> -#define __XEN_LATEST_INTERFACE_VERSION__ 0x00040300
> +#define __XEN_LATEST_INTERFACE_VERSION__ 0x00040400
>
> #if defined(__XEN__) || defined(__XEN_TOOLS__)
> /* Xen is built with matching headers and implements the latest interface. */
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