From: Marcus Granado <marcus.granado@citrix.com>
To: xen-devel <xen-devel@lists.xensource.com>
Cc: George Dunlap <George.Dunlap@eu.citrix.com>
Subject: [PATCH 2/3] xenoprof: Handle 32-bit guest stacks properly in a 64-bit hypervisor
Date: Fri, 20 Jan 2012 18:45:00 +0000 [thread overview]
Message-ID: <4F19B62C.9020402@citrix.com> (raw)
[-- Attachment #1: Type: text/plain, Size: 2885 bytes --]
xenoprof: Handle 32-bit guest stacks properly in a 64-bit hypervisor
The dump_guest_backtrace() function attempted to walk the stack
based on the assumption that the guest and hypervisor pointer sizes
were the same; thus any 32-bit guest running under 64-bit hypervisor
would have unreliable results.
In 64-bit mode, read the 32-bit stack frame properly.
Signed-off-by: Marcus Granado <marcus.granado@eu.citrix.com>
Signed-off-by: George Dunlap <george.dunlap@eu.citrix.com>
diff -r f6953e89913f -r 21e7744a52b1 xen/arch/x86/oprofile/backtrace.c
--- a/xen/arch/x86/oprofile/backtrace.c Wed Jan 18 17:23:02 2012 +0000
+++ b/xen/arch/x86/oprofile/backtrace.c Wed Jan 18 17:35:06 2012 +0000
@@ -20,6 +20,13 @@ struct frame_head {
unsigned long ret;
} __attribute__((packed));
+#ifdef CONFIG_X86_64
+struct frame_head_32bit {
+ uint32_t ebp;
+ unsigned long ret;
+} __attribute__((packed));
+#endif
+
static struct frame_head *
dump_hypervisor_backtrace(struct domain *d, struct vcpu *vcpu,
struct frame_head * head, int mode)
@@ -35,19 +42,46 @@ dump_hypervisor_backtrace(struct domain
return head->ebp;
}
+#ifdef CONFIG_X86_64
+static inline int is_32bit_vcpu(struct vcpu *vcpu)
+{
+ if (is_hvm_vcpu(vcpu))
+ return !hvm_long_mode_enabled(vcpu);
+ else
+ return is_pv_32bit_vcpu(vcpu);
+}
+#endif
+
static struct frame_head *
dump_guest_backtrace(struct domain *d, struct vcpu *vcpu,
struct frame_head * head, int mode)
{
struct frame_head bufhead[2];
XEN_GUEST_HANDLE(char) guest_head = guest_handle_from_ptr(head, char);
-
- /* Also check accessibility of one struct frame_head beyond */
- if (!guest_handle_okay(guest_head, sizeof(bufhead)))
- return 0;
- if (__copy_from_guest_offset((char *)bufhead, guest_head, 0,
- sizeof(bufhead)))
- return 0;
+
+#ifdef CONFIG_X86_64
+ if ( is_32bit_vcpu(vcpu) )
+ {
+ struct frame_head_32bit bufhead32[2];
+ /* Also check accessibility of one struct frame_head beyond */
+ if (!guest_handle_okay(guest_head, sizeof(bufhead32)))
+ return 0;
+ if (__copy_from_guest_offset((char *)bufhead32, guest_head, 0,
+ sizeof(bufhead32)))
+ return 0;
+ bufhead[0].ebp=(struct frame_head *)(unsigned
long)bufhead32[0].ebp;
+ bufhead[0].ret=bufhead32[0].ret;
+ }
+ else
+#endif
+ {
+ /* Also check accessibility of one struct frame_head beyond */
+ if (!guest_handle_okay(guest_head, sizeof(bufhead)))
+ return 0;
+ if (__copy_from_guest_offset((char *)bufhead, guest_head, 0,
+ sizeof(bufhead)))
+ return 0;
+ }
if (!xenoprof_add_trace(d, vcpu, bufhead[0].ret, mode))
return 0;
[-- Attachment #2: xenoprof-handle-32-bit-guest-stacks.diff --]
[-- Type: text/x-patch, Size: 2861 bytes --]
xenoprof: Handle 32-bit guest stacks properly in a 64-bit hypervisor
The dump_guest_backtrace() function attempted to walk the stack
based on the assumption that the guest and hypervisor pointer sizes
were the same; thus any 32-bit guest running under 64-bit hypervisor
would have unreliable results.
In 64-bit mode, read the 32-bit stack frame properly.
Signed-off-by: Marcus Granado <marcus.granado@eu.citrix.com>
Signed-off-by: George Dunlap <george.dunlap@eu.citrix.com>
diff -r f6953e89913f -r 21e7744a52b1 xen/arch/x86/oprofile/backtrace.c
--- a/xen/arch/x86/oprofile/backtrace.c Wed Jan 18 17:23:02 2012 +0000
+++ b/xen/arch/x86/oprofile/backtrace.c Wed Jan 18 17:35:06 2012 +0000
@@ -20,6 +20,13 @@ struct frame_head {
unsigned long ret;
} __attribute__((packed));
+#ifdef CONFIG_X86_64
+struct frame_head_32bit {
+ uint32_t ebp;
+ unsigned long ret;
+} __attribute__((packed));
+#endif
+
static struct frame_head *
dump_hypervisor_backtrace(struct domain *d, struct vcpu *vcpu,
struct frame_head * head, int mode)
@@ -35,19 +42,46 @@ dump_hypervisor_backtrace(struct domain
return head->ebp;
}
+#ifdef CONFIG_X86_64
+static inline int is_32bit_vcpu(struct vcpu *vcpu)
+{
+ if (is_hvm_vcpu(vcpu))
+ return !hvm_long_mode_enabled(vcpu);
+ else
+ return is_pv_32bit_vcpu(vcpu);
+}
+#endif
+
static struct frame_head *
dump_guest_backtrace(struct domain *d, struct vcpu *vcpu,
struct frame_head * head, int mode)
{
struct frame_head bufhead[2];
XEN_GUEST_HANDLE(char) guest_head = guest_handle_from_ptr(head, char);
-
- /* Also check accessibility of one struct frame_head beyond */
- if (!guest_handle_okay(guest_head, sizeof(bufhead)))
- return 0;
- if (__copy_from_guest_offset((char *)bufhead, guest_head, 0,
- sizeof(bufhead)))
- return 0;
+
+#ifdef CONFIG_X86_64
+ if ( is_32bit_vcpu(vcpu) )
+ {
+ struct frame_head_32bit bufhead32[2];
+ /* Also check accessibility of one struct frame_head beyond */
+ if (!guest_handle_okay(guest_head, sizeof(bufhead32)))
+ return 0;
+ if (__copy_from_guest_offset((char *)bufhead32, guest_head, 0,
+ sizeof(bufhead32)))
+ return 0;
+ bufhead[0].ebp=(struct frame_head *)(unsigned long)bufhead32[0].ebp;
+ bufhead[0].ret=bufhead32[0].ret;
+ }
+ else
+#endif
+ {
+ /* Also check accessibility of one struct frame_head beyond */
+ if (!guest_handle_okay(guest_head, sizeof(bufhead)))
+ return 0;
+ if (__copy_from_guest_offset((char *)bufhead, guest_head, 0,
+ sizeof(bufhead)))
+ return 0;
+ }
if (!xenoprof_add_trace(d, vcpu, bufhead[0].ret, mode))
return 0;
[-- Attachment #3: Type: text/plain, Size: 138 bytes --]
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next reply other threads:[~2012-01-20 18:45 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-20 18:45 Marcus Granado [this message]
2012-01-23 9:50 ` [PATCH 2/3] xenoprof: Handle 32-bit guest stacks properly in a 64-bit hypervisor Jan Beulich
2012-01-24 19:27 ` Marcus Granado
2012-01-25 7:52 ` Jan Beulich
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