* [PATCH 1/2] arm/traps: fix bug in dump_guest_s1_walk L1 page table offset computation
@ 2016-07-19 17:15 Jonathan Daugherty
2016-07-19 17:15 ` [PATCH 2/2] arm/traps: fix bug in dump_guest_s1_walk handling of level 2 page tables Jonathan Daugherty
2016-07-20 12:23 ` [PATCH 1/2] arm/traps: fix bug in dump_guest_s1_walk L1 page table offset computation Julien Grall
0 siblings, 2 replies; 5+ messages in thread
From: Jonathan Daugherty @ 2016-07-19 17:15 UTC (permalink / raw)
To: xen-devel; +Cc: julien.grall, sstabellini, Jonathan Daugherty
The dump_guest_s1_walk function was incorrectly using the top 10 bits of
the virtual address to select the L1 page table index. The correct
amount is 12 bits, resulting in a shift of 20 bits rather than 22.
For more details, see the ARMv7-A ARM, section B3.5, "Short-descriptor
translation table format."
Signed-off-by: Jonathan Daugherty <jtd@galois.com>
---
xen/arch/arm/traps.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
index a2eb1da..0c10c4d 100644
--- a/xen/arch/arm/traps.c
+++ b/xen/arch/arm/traps.c
@@ -2346,7 +2346,7 @@ void dump_guest_s1_walk(struct domain *d, vaddr_t addr)
}
first = map_domain_page(mfn);
- offset = addr >> (12+10);
+ offset = addr >> (12+8);
printk("1ST[0x%"PRIx32"] (0x%"PRIpaddr") = 0x%08"PRIx32"\n",
offset, pfn_to_paddr(mfn_x(mfn)), first[offset]);
if ( !(first[offset] & 0x1) ||
--
2.9.2
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^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH 2/2] arm/traps: fix bug in dump_guest_s1_walk handling of level 2 page tables
2016-07-19 17:15 [PATCH 1/2] arm/traps: fix bug in dump_guest_s1_walk L1 page table offset computation Jonathan Daugherty
@ 2016-07-19 17:15 ` Jonathan Daugherty
2016-07-20 12:25 ` Julien Grall
2016-07-20 12:23 ` [PATCH 1/2] arm/traps: fix bug in dump_guest_s1_walk L1 page table offset computation Julien Grall
1 sibling, 1 reply; 5+ messages in thread
From: Jonathan Daugherty @ 2016-07-19 17:15 UTC (permalink / raw)
To: xen-devel; +Cc: julien.grall, sstabellini, Jonathan Daugherty
dump_guest_s1_walk intends to walk to level 2 page table entries but
was failing to do so because of a check that caused level 2 page table
descriptors to be ignored. This change fixes the check so that level 2
page table walks occur as intended by ignoring descriptors unless their
low two bits match the expected sequence [0,1].
For more information, see the ARMv7-A ARM, section B3.5.
Signed-off-by: Jonathan Daugherty <jtd@galois.com>
---
xen/arch/arm/traps.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
index 0c10c4d..dfb1949 100644
--- a/xen/arch/arm/traps.c
+++ b/xen/arch/arm/traps.c
@@ -2350,7 +2350,7 @@ void dump_guest_s1_walk(struct domain *d, vaddr_t addr)
printk("1ST[0x%"PRIx32"] (0x%"PRIpaddr") = 0x%08"PRIx32"\n",
offset, pfn_to_paddr(mfn_x(mfn)), first[offset]);
if ( !(first[offset] & 0x1) ||
- !(first[offset] & 0x2) )
+ (first[offset] & 0x2) )
goto done;
mfn = p2m_lookup(d, _gfn(paddr_to_pfn(first[offset])), NULL);
--
2.9.2
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^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH 1/2] arm/traps: fix bug in dump_guest_s1_walk L1 page table offset computation
2016-07-19 17:15 [PATCH 1/2] arm/traps: fix bug in dump_guest_s1_walk L1 page table offset computation Jonathan Daugherty
2016-07-19 17:15 ` [PATCH 2/2] arm/traps: fix bug in dump_guest_s1_walk handling of level 2 page tables Jonathan Daugherty
@ 2016-07-20 12:23 ` Julien Grall
1 sibling, 0 replies; 5+ messages in thread
From: Julien Grall @ 2016-07-20 12:23 UTC (permalink / raw)
To: Jonathan Daugherty, xen-devel; +Cc: sstabellini
Hi Jonathan,
Thank you for sending the bug fix.
On 19/07/16 18:15, Jonathan Daugherty wrote:
> The dump_guest_s1_walk function was incorrectly using the top 10 bits of
> the virtual address to select the L1 page table index. The correct
> amount is 12 bits, resulting in a shift of 20 bits rather than 22.
>
> For more details, see the ARMv7-A ARM, section B3.5, "Short-descriptor
NIT: Could you specify the version of the spec (i.e something similar to
ARM DDI 0406C.c)?
> translation table format."
>
> Signed-off-by: Jonathan Daugherty <jtd@galois.com>
With the suggestion above:
Reviewed-by: Julien Grall <julien.grall@arm.com>
Regards,
> ---
> xen/arch/arm/traps.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
> index a2eb1da..0c10c4d 100644
> --- a/xen/arch/arm/traps.c
> +++ b/xen/arch/arm/traps.c
> @@ -2346,7 +2346,7 @@ void dump_guest_s1_walk(struct domain *d, vaddr_t addr)
> }
> first = map_domain_page(mfn);
>
> - offset = addr >> (12+10);
> + offset = addr >> (12+8);
> printk("1ST[0x%"PRIx32"] (0x%"PRIpaddr") = 0x%08"PRIx32"\n",
> offset, pfn_to_paddr(mfn_x(mfn)), first[offset]);
> if ( !(first[offset] & 0x1) ||
>
--
Julien Grall
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^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH 2/2] arm/traps: fix bug in dump_guest_s1_walk handling of level 2 page tables
2016-07-19 17:15 ` [PATCH 2/2] arm/traps: fix bug in dump_guest_s1_walk handling of level 2 page tables Jonathan Daugherty
@ 2016-07-20 12:25 ` Julien Grall
0 siblings, 0 replies; 5+ messages in thread
From: Julien Grall @ 2016-07-20 12:25 UTC (permalink / raw)
To: Jonathan Daugherty, xen-devel; +Cc: sstabellini
On 19/07/16 18:15, Jonathan Daugherty wrote:
> dump_guest_s1_walk intends to walk to level 2 page table entries but
> was failing to do so because of a check that caused level 2 page table
> descriptors to be ignored. This change fixes the check so that level 2
> page table walks occur as intended by ignoring descriptors unless their
> low two bits match the expected sequence [0,1].
>
> For more information, see the ARMv7-A ARM, section B3.5.
NIT: Could you specify the version of the spec (i.e something similar to
ARM DDI 0406C.c)?
Also, to be precise the section would be B3.5.1.
>
> Signed-off-by: Jonathan Daugherty <jtd@galois.com>
Reviewed-by: Julien Grall <julien.grall@arm.com>
Regards,
> ---
> xen/arch/arm/traps.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
> index 0c10c4d..dfb1949 100644
> --- a/xen/arch/arm/traps.c
> +++ b/xen/arch/arm/traps.c
> @@ -2350,7 +2350,7 @@ void dump_guest_s1_walk(struct domain *d, vaddr_t addr)
> printk("1ST[0x%"PRIx32"] (0x%"PRIpaddr") = 0x%08"PRIx32"\n",
> offset, pfn_to_paddr(mfn_x(mfn)), first[offset]);
> if ( !(first[offset] & 0x1) ||
> - !(first[offset] & 0x2) )
> + (first[offset] & 0x2) )
> goto done;
>
> mfn = p2m_lookup(d, _gfn(paddr_to_pfn(first[offset])), NULL);
>
--
Julien Grall
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^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH 1/2] arm/traps: fix bug in dump_guest_s1_walk L1 page table offset computation
@ 2016-07-20 16:10 Jonathan Daugherty
0 siblings, 0 replies; 5+ messages in thread
From: Jonathan Daugherty @ 2016-07-20 16:10 UTC (permalink / raw)
To: xen-devel; +Cc: julien.grall, sstabellini, Jonathan Daugherty
The dump_guest_s1_walk function was incorrectly using the top 10 bits of
the virtual address to select the L1 page table index. The correct
amount is 12 bits, resulting in a shift of 20 bits rather than 22.
For more details, see the ARMv7-A ARM DDI 0406C.b, section B3.5,
"Short-descriptor translation table format."
Signed-off-by: Jonathan Daugherty <jtd@galois.com>
---
xen/arch/arm/traps.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
index a2eb1da..0c10c4d 100644
--- a/xen/arch/arm/traps.c
+++ b/xen/arch/arm/traps.c
@@ -2346,7 +2346,7 @@ void dump_guest_s1_walk(struct domain *d, vaddr_t addr)
}
first = map_domain_page(mfn);
- offset = addr >> (12+10);
+ offset = addr >> (12+8);
printk("1ST[0x%"PRIx32"] (0x%"PRIpaddr") = 0x%08"PRIx32"\n",
offset, pfn_to_paddr(mfn_x(mfn)), first[offset]);
if ( !(first[offset] & 0x1) ||
--
2.9.2
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2016-07-19 17:15 [PATCH 1/2] arm/traps: fix bug in dump_guest_s1_walk L1 page table offset computation Jonathan Daugherty
2016-07-19 17:15 ` [PATCH 2/2] arm/traps: fix bug in dump_guest_s1_walk handling of level 2 page tables Jonathan Daugherty
2016-07-20 12:25 ` Julien Grall
2016-07-20 12:23 ` [PATCH 1/2] arm/traps: fix bug in dump_guest_s1_walk L1 page table offset computation Julien Grall
2016-07-20 16:10 Jonathan Daugherty
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