* [PATCH] x86: drop setup_idle_pagetable()
@ 2013-06-12 14:59 Jan Beulich
2013-06-12 15:06 ` Andrew Cooper
` (2 more replies)
0 siblings, 3 replies; 5+ messages in thread
From: Jan Beulich @ 2013-06-12 14:59 UTC (permalink / raw)
To: xen-devel; +Cc: George Dunlap, Keir Fraser
[-- Attachment #1: Type: text/plain, Size: 1475 bytes --]
With vcpu->domain->arch.perdomain_l3_pg no longer getting set up for
the idle domain, this creates an invalid L4 entry (due to translating
a NULL struct page_info pointer to a physical address).
Signed-off-by: Jan Beulich <jbeulich@suse.com>
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -185,7 +185,6 @@ static void __init init_idle_domain(void
scheduler_init();
set_current(idle_vcpu[0]);
this_cpu(curr_vcpu) = current;
- setup_idle_pagetable();
}
void __devinit srat_detect_node(int cpu)
--- a/xen/arch/x86/x86_64/mm.c
+++ b/xen/arch/x86/x86_64/mm.c
@@ -810,14 +810,6 @@ void __init paging_init(void)
panic("Not enough memory for m2p table\n");
}
-void __init setup_idle_pagetable(void)
-{
- /* Install per-domain mappings for idle domain. */
- l4e_write(&idle_pg_table[l4_table_offset(PERDOMAIN_VIRT_START)],
- l4e_from_page(idle_vcpu[0]->domain->arch.perdomain_l3_pg,
- __PAGE_HYPERVISOR));
-}
-
void __init zap_low_mappings(void)
{
BUG_ON(num_online_cpus() != 1);
--- a/xen/include/asm-x86/page.h
+++ b/xen/include/asm-x86/page.h
@@ -286,7 +286,6 @@ extern l2_pgentry_t l2_identmap[4*L2_PAG
extern l1_pgentry_t l1_identmap[L1_PAGETABLE_ENTRIES],
l1_fixmap[L1_PAGETABLE_ENTRIES];
void paging_init(void);
-void setup_idle_pagetable(void);
#endif /* !defined(__ASSEMBLY__) */
#define _PAGE_PRESENT _AC(0x001,U)
[-- Attachment #2: x86-drop-setup-idle-pagetable.patch --]
[-- Type: text/plain, Size: 1505 bytes --]
x86: drop setup_idle_pagetable()
With vcpu->domain->arch.perdomain_l3_pg no longer getting set up for
the idle domain, this creates an invalid L4 entry (due to translating
a NULL struct page_info pointer to a physical address).
Signed-off-by: Jan Beulich <jbeulich@suse.com>
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -185,7 +185,6 @@ static void __init init_idle_domain(void
scheduler_init();
set_current(idle_vcpu[0]);
this_cpu(curr_vcpu) = current;
- setup_idle_pagetable();
}
void __devinit srat_detect_node(int cpu)
--- a/xen/arch/x86/x86_64/mm.c
+++ b/xen/arch/x86/x86_64/mm.c
@@ -810,14 +810,6 @@ void __init paging_init(void)
panic("Not enough memory for m2p table\n");
}
-void __init setup_idle_pagetable(void)
-{
- /* Install per-domain mappings for idle domain. */
- l4e_write(&idle_pg_table[l4_table_offset(PERDOMAIN_VIRT_START)],
- l4e_from_page(idle_vcpu[0]->domain->arch.perdomain_l3_pg,
- __PAGE_HYPERVISOR));
-}
-
void __init zap_low_mappings(void)
{
BUG_ON(num_online_cpus() != 1);
--- a/xen/include/asm-x86/page.h
+++ b/xen/include/asm-x86/page.h
@@ -286,7 +286,6 @@ extern l2_pgentry_t l2_identmap[4*L2_PAG
extern l1_pgentry_t l1_identmap[L1_PAGETABLE_ENTRIES],
l1_fixmap[L1_PAGETABLE_ENTRIES];
void paging_init(void);
-void setup_idle_pagetable(void);
#endif /* !defined(__ASSEMBLY__) */
#define _PAGE_PRESENT _AC(0x001,U)
[-- Attachment #3: Type: text/plain, Size: 126 bytes --]
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^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] x86: drop setup_idle_pagetable()
2013-06-12 14:59 [PATCH] x86: drop setup_idle_pagetable() Jan Beulich
@ 2013-06-12 15:06 ` Andrew Cooper
2013-06-12 15:12 ` Keir Fraser
2013-06-12 15:14 ` George Dunlap
2 siblings, 0 replies; 5+ messages in thread
From: Andrew Cooper @ 2013-06-12 15:06 UTC (permalink / raw)
To: Jan Beulich; +Cc: George Dunlap, Keir (Xen.org), xen-devel
On 12/06/13 15:59, Jan Beulich wrote:
> With vcpu->domain->arch.perdomain_l3_pg no longer getting set up for
> the idle domain, this creates an invalid L4 entry (due to translating
> a NULL struct page_info pointer to a physical address).
>
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Is it perhaps prudent to extend some of the $FOO_from_page() macros to
guard against NULL pointers in debug builds?
~Andrew
>
> --- a/xen/arch/x86/setup.c
> +++ b/xen/arch/x86/setup.c
> @@ -185,7 +185,6 @@ static void __init init_idle_domain(void
> scheduler_init();
> set_current(idle_vcpu[0]);
> this_cpu(curr_vcpu) = current;
> - setup_idle_pagetable();
> }
>
> void __devinit srat_detect_node(int cpu)
> --- a/xen/arch/x86/x86_64/mm.c
> +++ b/xen/arch/x86/x86_64/mm.c
> @@ -810,14 +810,6 @@ void __init paging_init(void)
> panic("Not enough memory for m2p table\n");
> }
>
> -void __init setup_idle_pagetable(void)
> -{
> - /* Install per-domain mappings for idle domain. */
> - l4e_write(&idle_pg_table[l4_table_offset(PERDOMAIN_VIRT_START)],
> - l4e_from_page(idle_vcpu[0]->domain->arch.perdomain_l3_pg,
> - __PAGE_HYPERVISOR));
> -}
> -
> void __init zap_low_mappings(void)
> {
> BUG_ON(num_online_cpus() != 1);
> --- a/xen/include/asm-x86/page.h
> +++ b/xen/include/asm-x86/page.h
> @@ -286,7 +286,6 @@ extern l2_pgentry_t l2_identmap[4*L2_PAG
> extern l1_pgentry_t l1_identmap[L1_PAGETABLE_ENTRIES],
> l1_fixmap[L1_PAGETABLE_ENTRIES];
> void paging_init(void);
> -void setup_idle_pagetable(void);
> #endif /* !defined(__ASSEMBLY__) */
>
> #define _PAGE_PRESENT _AC(0x001,U)
>
>
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] x86: drop setup_idle_pagetable()
2013-06-12 14:59 [PATCH] x86: drop setup_idle_pagetable() Jan Beulich
2013-06-12 15:06 ` Andrew Cooper
@ 2013-06-12 15:12 ` Keir Fraser
2013-06-12 15:14 ` George Dunlap
2 siblings, 0 replies; 5+ messages in thread
From: Keir Fraser @ 2013-06-12 15:12 UTC (permalink / raw)
To: Jan Beulich, xen-devel; +Cc: George Dunlap
On 12/06/2013 15:59, "Jan Beulich" <JBeulich@suse.com> wrote:
> With vcpu->domain->arch.perdomain_l3_pg no longer getting set up for
> the idle domain, this creates an invalid L4 entry (due to translating
> a NULL struct page_info pointer to a physical address).
>
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Keir Fraser <keir@xen.org>
> --- a/xen/arch/x86/setup.c
> +++ b/xen/arch/x86/setup.c
> @@ -185,7 +185,6 @@ static void __init init_idle_domain(void
> scheduler_init();
> set_current(idle_vcpu[0]);
> this_cpu(curr_vcpu) = current;
> - setup_idle_pagetable();
> }
>
> void __devinit srat_detect_node(int cpu)
> --- a/xen/arch/x86/x86_64/mm.c
> +++ b/xen/arch/x86/x86_64/mm.c
> @@ -810,14 +810,6 @@ void __init paging_init(void)
> panic("Not enough memory for m2p table\n");
> }
>
> -void __init setup_idle_pagetable(void)
> -{
> - /* Install per-domain mappings for idle domain. */
> - l4e_write(&idle_pg_table[l4_table_offset(PERDOMAIN_VIRT_START)],
> - l4e_from_page(idle_vcpu[0]->domain->arch.perdomain_l3_pg,
> - __PAGE_HYPERVISOR));
> -}
> -
> void __init zap_low_mappings(void)
> {
> BUG_ON(num_online_cpus() != 1);
> --- a/xen/include/asm-x86/page.h
> +++ b/xen/include/asm-x86/page.h
> @@ -286,7 +286,6 @@ extern l2_pgentry_t l2_identmap[4*L2_PAG
> extern l1_pgentry_t l1_identmap[L1_PAGETABLE_ENTRIES],
> l1_fixmap[L1_PAGETABLE_ENTRIES];
> void paging_init(void);
> -void setup_idle_pagetable(void);
> #endif /* !defined(__ASSEMBLY__) */
>
> #define _PAGE_PRESENT _AC(0x001,U)
>
>
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] x86: drop setup_idle_pagetable()
2013-06-12 14:59 [PATCH] x86: drop setup_idle_pagetable() Jan Beulich
2013-06-12 15:06 ` Andrew Cooper
2013-06-12 15:12 ` Keir Fraser
@ 2013-06-12 15:14 ` George Dunlap
2013-06-12 15:25 ` Keir Fraser
2 siblings, 1 reply; 5+ messages in thread
From: George Dunlap @ 2013-06-12 15:14 UTC (permalink / raw)
To: Jan Beulich; +Cc: Keir Fraser, xen-devel
On 12/06/13 15:59, Jan Beulich wrote:
> With vcpu->domain->arch.perdomain_l3_pg no longer getting set up for
> the idle domain, this creates an invalid L4 entry (due to translating
> a NULL struct page_info pointer to a physical address).
>
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
I don't think it buys very much awesomeness, but it should certainly be
pretty low risk.
Acked-by: George Dunlap <george.dunlap@eu.citrix.com>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] x86: drop setup_idle_pagetable()
2013-06-12 15:14 ` George Dunlap
@ 2013-06-12 15:25 ` Keir Fraser
0 siblings, 0 replies; 5+ messages in thread
From: Keir Fraser @ 2013-06-12 15:25 UTC (permalink / raw)
To: George Dunlap, Jan Beulich; +Cc: xen-devel
On 12/06/2013 16:14, "George Dunlap" <george.dunlap@eu.citrix.com> wrote:
> On 12/06/13 15:59, Jan Beulich wrote:
>> With vcpu->domain->arch.perdomain_l3_pg no longer getting set up for
>> the idle domain, this creates an invalid L4 entry (due to translating
>> a NULL struct page_info pointer to a physical address).
>>
>> Signed-off-by: Jan Beulich <jbeulich@suse.com>
>
> I don't think it buys very much awesomeness, but it should certainly be
> pretty low risk.
>
> Acked-by: George Dunlap <george.dunlap@eu.citrix.com>
Pagetable entries pointing into the wilderness are actively dangerous. At
the very least they can cause cache-attribute collisions. This is a real bug
fix.
-- Keir
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2013-06-12 15:25 UTC | newest]
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2013-06-12 14:59 [PATCH] x86: drop setup_idle_pagetable() Jan Beulich
2013-06-12 15:06 ` Andrew Cooper
2013-06-12 15:12 ` Keir Fraser
2013-06-12 15:14 ` George Dunlap
2013-06-12 15:25 ` Keir Fraser
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