* [PATCH v2] libelf: allow having HYPERCALL_PAGE entry before VIRT_BASE in __xen_guest section.
@ 2017-10-11 13:35 gregory.herrero
2017-10-11 13:42 ` Jan Beulich
0 siblings, 1 reply; 2+ messages in thread
From: gregory.herrero @ 2017-10-11 13:35 UTC (permalink / raw)
To: xen-devel
Cc: sstabellini, wei.liu2, konrad.wilk, George.Dunlap, ian.jackson,
tim, jbeulich, andrew.cooper3, Gregory Herrero
From: Gregory Herrero <gregory.herrero@oracle.com>
When filling __xen_guest section of a guest, user may define
HYPERCALL_PAGE earlier than VIRT_BASE in the section leading to an
incorrect hypercall page address since an undefined virt_base could be
used to compute hypercall page address.
If there is no VIRT_BASE entry in __xen_guest section, default value of
0 is used for virt_base. Thus, setting hypercall page address to
HYPERCALL_PAGE value is correct in this case too.
Signed-off-by: Gregory Herrero <gregory.herrero@oracle.com>
---
Changed since v1:
* set virt_hypercall once after the while loop.
---
xen/common/libelf/libelf-dominfo.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)
diff --git a/xen/common/libelf/libelf-dominfo.c b/xen/common/libelf/libelf-dominfo.c
index a52900c00cd..eaeb774ff3d 100644
--- a/xen/common/libelf/libelf-dominfo.c
+++ b/xen/common/libelf/libelf-dominfo.c
@@ -269,6 +269,7 @@ elf_errorstatus elf_xen_parse_guest_info(struct elf_binary *elf,
elf_ptrval h;
unsigned char name[32], value[128];
unsigned len;
+ elf_errorstatus ret = 0;
h = parms->guest_info;
#define STAR(h) (elf_access_unsigned(elf, (h), 0, 1))
@@ -336,16 +337,22 @@ elf_errorstatus elf_xen_parse_guest_info(struct elf_binary *elf,
if ( !strcmp(name, "ELF_PADDR_OFFSET") )
parms->elf_paddr_offset = strtoull(value, NULL, 0);
if ( !strcmp(name, "HYPERCALL_PAGE") )
- parms->virt_hypercall = (strtoull(value, NULL, 0) << 12) +
- parms->virt_base;
+ parms->virt_hypercall = (strtoull(value, NULL, 0) << 12);
/* other */
if ( !strcmp(name, "FEATURES") )
if ( elf_xen_parse_features(value, parms->f_supported,
parms->f_required) )
- return -1;
+ {
+ ret = -1;
+ break;
+ }
}
- return 0;
+ if ( (parms->virt_base != UNSET_ADDR) &&
+ (parms->virt_hypercall != UNSET_ADDR) )
+ parms->virt_hypercall += parms->virt_base;
+
+ return ret;
}
/* ------------------------------------------------------------------------ */
--
2.14.1
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^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v2] libelf: allow having HYPERCALL_PAGE entry before VIRT_BASE in __xen_guest section.
2017-10-11 13:35 [PATCH v2] libelf: allow having HYPERCALL_PAGE entry before VIRT_BASE in __xen_guest section gregory.herrero
@ 2017-10-11 13:42 ` Jan Beulich
0 siblings, 0 replies; 2+ messages in thread
From: Jan Beulich @ 2017-10-11 13:42 UTC (permalink / raw)
To: gregory.herrero
Cc: tim, sstabellini, wei.liu2, konrad.wilk, George.Dunlap,
andrew.cooper3, ian.jackson, xen-devel
>>> On 11.10.17 at 15:35, <gregory.herrero@oracle.com> wrote:
> @@ -336,16 +337,22 @@ elf_errorstatus elf_xen_parse_guest_info(struct elf_binary *elf,
> if ( !strcmp(name, "ELF_PADDR_OFFSET") )
> parms->elf_paddr_offset = strtoull(value, NULL, 0);
> if ( !strcmp(name, "HYPERCALL_PAGE") )
> - parms->virt_hypercall = (strtoull(value, NULL, 0) << 12) +
> - parms->virt_base;
> + parms->virt_hypercall = (strtoull(value, NULL, 0) << 12);
Please also drop the now pointless parentheses.
> /* other */
> if ( !strcmp(name, "FEATURES") )
> if ( elf_xen_parse_features(value, parms->f_supported,
> parms->f_required) )
> - return -1;
> + {
> + ret = -1;
> + break;
> + }
> }
> - return 0;
> + if ( (parms->virt_base != UNSET_ADDR) &&
Please add a blank line ahead of this addition.
With those taken care of
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Jan
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2017-10-11 13:35 [PATCH v2] libelf: allow having HYPERCALL_PAGE entry before VIRT_BASE in __xen_guest section gregory.herrero
2017-10-11 13:42 ` Jan Beulich
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