* [PATCH] x86: rework hypercall argument translation area setup
@ 2013-02-21 11:42 Jan Beulich
2013-02-21 12:08 ` Keir Fraser
0 siblings, 1 reply; 6+ messages in thread
From: Jan Beulich @ 2013-02-21 11:42 UTC (permalink / raw)
To: xen-devel
[-- Attachment #1: Type: text/plain, Size: 8305 bytes --]
Rather than using an order-1 Xen heap allocation, use (currently 2)
individual domain heap pages to populate space in the per-domain
mapping area.
Also fix an off-by-one mistake in is_compat_arg_xlat_range().
Signed-off-by: Jan Beulich <jbeulich@suse.com>
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -642,6 +642,14 @@ void arch_domain_destroy(struct domain *
free_domheap_page(d->arch.perdomain_l2_pg[i]);
free_domheap_page(d->arch.perdomain_l3_pg);
+ if ( d->arch.arg_xlat_l1_pg )
+ {
+ for ( i = 0; i < PFN_UP(MAX_VIRT_CPUS << ARG_XLAT_VA_SHIFT); ++i )
+ if ( d->arch.arg_xlat_l1_pg[i] )
+ free_domheap_page(d->arch.arg_xlat_l1_pg[i]);
+ xfree(d->arch.arg_xlat_l1_pg);
+ }
+
free_xenheap_page(d->shared_info);
cleanup_domain_irq_mapping(d);
}
--- a/xen/arch/x86/usercopy.c
+++ b/xen/arch/x86/usercopy.c
@@ -6,8 +6,8 @@
* Copyright 2002 Andi Kleen <ak@suse.de>
*/
-#include <xen/config.h>
#include <xen/lib.h>
+#include <xen/sched.h>
#include <asm/uaccess.h>
unsigned long __copy_to_user_ll(void __user *to, const void *from, unsigned n)
--- a/xen/arch/x86/x86_64/mm.c
+++ b/xen/arch/x86/x86_64/mm.c
@@ -832,27 +832,93 @@ void __init zap_low_mappings(void)
__PAGE_HYPERVISOR);
}
-void *compat_arg_xlat_virt_base(void)
-{
- return current->arch.compat_arg_xlat;
-}
-
int setup_compat_arg_xlat(struct vcpu *v)
{
- unsigned int order = get_order_from_bytes(COMPAT_ARG_XLAT_SIZE);
+ struct domain *d = v->domain;
+ struct page_info *pg;
+ unsigned int idx, i;
+ l1_pgentry_t *l1tab;
+
+ if ( !d->arch.perdomain_l2_pg[ARG_XLAT_SLOT] )
+ {
+ l3_pgentry_t *l3tab;
+
+ pg = alloc_domheap_page(NULL, MEMF_node(domain_to_node(d)));
+ if ( !pg )
+ return -ENOMEM;
+ clear_domain_page(page_to_mfn(pg));
+ d->arch.perdomain_l2_pg[ARG_XLAT_SLOT] = pg;
+
+ l3tab = __map_domain_page(d->arch.perdomain_l3_pg);
+ l3tab[l3_table_offset(ARG_XLAT_VIRT_START)] =
+ l3e_from_page(pg, __PAGE_HYPERVISOR);
+ unmap_domain_page(l3tab);
+ }
+
+ BUILD_BUG_ON((MAX_VIRT_CPUS << ARG_XLAT_VA_SHIFT) >
+ (PERDOMAIN_SLOT_MBYTES << 20));
+
+ if ( !d->arch.arg_xlat_l1_pg )
+ d->arch.arg_xlat_l1_pg = xzalloc_array(struct page_info *,
+ PFN_UP(MAX_VIRT_CPUS <<
+ ARG_XLAT_VA_SHIFT));
+ if ( !d->arch.arg_xlat_l1_pg )
+ return -ENOMEM;
+
+ idx = l2_table_offset(ARG_XLAT_START(v));
+ if ( !d->arch.arg_xlat_l1_pg[idx] )
+ {
+ l2_pgentry_t *l2tab;
+
+ pg = alloc_domheap_page(NULL, MEMF_node(domain_to_node(d)));
+ if ( !pg )
+ return -ENOMEM;
+ clear_domain_page(page_to_mfn(pg));
+ d->arch.arg_xlat_l1_pg[idx] = pg;
+
+ l2tab = __map_domain_page(d->arch.perdomain_l2_pg[ARG_XLAT_SLOT]);
+ l2tab[idx] = l2e_from_page(pg, __PAGE_HYPERVISOR);
+ unmap_domain_page(l2tab);
+ }
- v->arch.compat_arg_xlat = alloc_xenheap_pages(order,
- MEMF_node(vcpu_to_node(v)));
+ l1tab = __map_domain_page(d->arch.arg_xlat_l1_pg[idx]);
+ idx = l1_table_offset(ARG_XLAT_START(v));
+ BUILD_BUG_ON(COMPAT_ARG_XLAT_SIZE > (1UL << ARG_XLAT_VA_SHIFT));
+ for ( i = 0; i < PFN_UP(COMPAT_ARG_XLAT_SIZE); ++i )
+ {
+ pg = alloc_domheap_page(NULL, MEMF_node(domain_to_node(d)));
+ if ( !pg )
+ return -ENOMEM;
+ l1tab[idx + i] = l1e_from_page(pg, __PAGE_HYPERVISOR);
+ }
+ unmap_domain_page(l1tab);
- return v->arch.compat_arg_xlat ? 0 : -ENOMEM;
+ return 0;
}
void free_compat_arg_xlat(struct vcpu *v)
{
- unsigned int order = get_order_from_bytes(COMPAT_ARG_XLAT_SIZE);
+ struct domain *d = v->domain;
+ unsigned long start = ARG_XLAT_START(v);
+ unsigned long va = start + COMPAT_ARG_XLAT_SIZE - 1;
+ l1_pgentry_t *l1tab =
+ __map_domain_page(d->arch.arg_xlat_l1_pg[l2_table_offset(start)]);
+
+ do {
+ l1_pgentry_t l1e = l1tab[l1_table_offset(va)];
+
+ if ( l1e_get_flags(l1e) & _PAGE_PRESENT )
+ {
+ struct page_info *pg = l1e_get_page(l1e);
+
+ l1tab[l1_table_offset(va)] = l1e_empty();
+ flush_tlb_one_mask(d->domain_dirty_cpumask, va);
+ free_domheap_page(pg);
+ }
+ va -= PAGE_SIZE;
+ } while ( va >= start );
- free_xenheap_pages(v->arch.compat_arg_xlat, order);
- v->arch.compat_arg_xlat = NULL;
+ unmap_domain_page(l1tab);
}
void cleanup_frame_table(struct mem_hotadd_info *info)
--- a/xen/include/asm-x86/config.h
+++ b/xen/include/asm-x86/config.h
@@ -212,7 +212,7 @@ extern unsigned char boot_edid_info[128]
/* Slot 260: per-domain mappings (including map cache). */
#define PERDOMAIN_VIRT_START (PML4_ADDR(260))
#define PERDOMAIN_SLOT_MBYTES (PML4_ENTRY_BYTES >> (20 + PAGETABLE_ORDER))
-#define PERDOMAIN_SLOTS 2
+#define PERDOMAIN_SLOTS 3
#define PERDOMAIN_VIRT_SLOT(s) (PERDOMAIN_VIRT_START + (s) * \
(PERDOMAIN_SLOT_MBYTES << 20))
/* Slot 261: machine-to-phys conversion table (256GB). */
@@ -304,6 +304,14 @@ extern unsigned long xen_phys_start;
#define LDT_VIRT_START(v) \
(GDT_VIRT_START(v) + (64*1024))
+/* Argument translation area. The 2nd to last per-domain-mapping sub-area. */
+#define ARG_XLAT_SLOT (PERDOMAIN_SLOTS - 2)
+/* Allow for at least one guard page (COMPAT_ARG_XLAT_SIZE being 2 pages): */
+#define ARG_XLAT_VA_SHIFT (2 + PAGE_SHIFT)
+#define ARG_XLAT_VIRT_START PERDOMAIN_VIRT_SLOT(ARG_XLAT_SLOT)
+#define ARG_XLAT_START(v) \
+ (ARG_XLAT_VIRT_START + ((v)->vcpu_id << ARG_XLAT_VA_SHIFT))
+
/* map_domain_page() map cache. The last per-domain-mapping sub-area. */
#define MAPCACHE_VCPU_ENTRIES (CONFIG_PAGING_LEVELS * CONFIG_PAGING_LEVELS)
#define MAPCACHE_ENTRIES (MAX_VIRT_CPUS * MAPCACHE_VCPU_ENTRIES)
@@ -313,7 +321,7 @@ extern unsigned long xen_phys_start;
MAPCACHE_ENTRIES * PAGE_SIZE)
#define PDPT_L1_ENTRIES \
- ((PERDOMAIN_VIRT_SLOT(PERDOMAIN_SLOTS - 1) - PERDOMAIN_VIRT_START) >> PAGE_SHIFT)
+ ((PERDOMAIN_VIRT_SLOT(PERDOMAIN_SLOTS - 2) - PERDOMAIN_VIRT_START) >> PAGE_SHIFT)
#define PDPT_L2_ENTRIES \
((PDPT_L1_ENTRIES + (1 << PAGETABLE_ORDER) - 1) >> PAGETABLE_ORDER)
--- a/xen/include/asm-x86/domain.h
+++ b/xen/include/asm-x86/domain.h
@@ -244,6 +244,7 @@ struct arch_domain
void **perdomain_pts;
struct page_info *perdomain_l2_pg[PERDOMAIN_SLOTS];
struct page_info *perdomain_l3_pg;
+ struct page_info **arg_xlat_l1_pg;
unsigned int hv_compat_vstart;
@@ -448,9 +449,6 @@ struct arch_vcpu
/* A secondary copy of the vcpu time info. */
XEN_GUEST_HANDLE(vcpu_time_info_t) time_info_guest;
-
- void *compat_arg_xlat;
-
} __cacheline_aligned;
/* Shorthands to improve code legibility. */
--- a/xen/include/asm-x86/x86_64/uaccess.h
+++ b/xen/include/asm-x86/x86_64/uaccess.h
@@ -1,16 +1,15 @@
#ifndef __X86_64_UACCESS_H
#define __X86_64_UACCESS_H
-#define COMPAT_ARG_XLAT_VIRT_BASE compat_arg_xlat_virt_base()
+#define COMPAT_ARG_XLAT_VIRT_BASE ((void *)ARG_XLAT_START(current))
#define COMPAT_ARG_XLAT_SIZE (2*PAGE_SIZE)
struct vcpu;
-void *compat_arg_xlat_virt_base(void);
int setup_compat_arg_xlat(struct vcpu *v);
void free_compat_arg_xlat(struct vcpu *v);
#define is_compat_arg_xlat_range(addr, size) ({ \
unsigned long __off; \
__off = (unsigned long)(addr) - (unsigned long)COMPAT_ARG_XLAT_VIRT_BASE; \
- (__off <= COMPAT_ARG_XLAT_SIZE) && \
+ (__off < COMPAT_ARG_XLAT_SIZE) && \
((__off + (unsigned long)(size)) <= COMPAT_ARG_XLAT_SIZE); \
})
[-- Attachment #2: x86-map-arg-xlat-area.patch --]
[-- Type: text/plain, Size: 8358 bytes --]
x86: rework hypercall argument translation area setup
Rather than using an order-1 Xen heap allocation, use (currently 2)
individual domain heap pages to populate space in the per-domain
mapping area.
Also fix an off-by-one mistake in is_compat_arg_xlat_range().
Signed-off-by: Jan Beulich <jbeulich@suse.com>
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -642,6 +642,14 @@ void arch_domain_destroy(struct domain *
free_domheap_page(d->arch.perdomain_l2_pg[i]);
free_domheap_page(d->arch.perdomain_l3_pg);
+ if ( d->arch.arg_xlat_l1_pg )
+ {
+ for ( i = 0; i < PFN_UP(MAX_VIRT_CPUS << ARG_XLAT_VA_SHIFT); ++i )
+ if ( d->arch.arg_xlat_l1_pg[i] )
+ free_domheap_page(d->arch.arg_xlat_l1_pg[i]);
+ xfree(d->arch.arg_xlat_l1_pg);
+ }
+
free_xenheap_page(d->shared_info);
cleanup_domain_irq_mapping(d);
}
--- a/xen/arch/x86/usercopy.c
+++ b/xen/arch/x86/usercopy.c
@@ -6,8 +6,8 @@
* Copyright 2002 Andi Kleen <ak@suse.de>
*/
-#include <xen/config.h>
#include <xen/lib.h>
+#include <xen/sched.h>
#include <asm/uaccess.h>
unsigned long __copy_to_user_ll(void __user *to, const void *from, unsigned n)
--- a/xen/arch/x86/x86_64/mm.c
+++ b/xen/arch/x86/x86_64/mm.c
@@ -832,27 +832,93 @@ void __init zap_low_mappings(void)
__PAGE_HYPERVISOR);
}
-void *compat_arg_xlat_virt_base(void)
-{
- return current->arch.compat_arg_xlat;
-}
-
int setup_compat_arg_xlat(struct vcpu *v)
{
- unsigned int order = get_order_from_bytes(COMPAT_ARG_XLAT_SIZE);
+ struct domain *d = v->domain;
+ struct page_info *pg;
+ unsigned int idx, i;
+ l1_pgentry_t *l1tab;
+
+ if ( !d->arch.perdomain_l2_pg[ARG_XLAT_SLOT] )
+ {
+ l3_pgentry_t *l3tab;
+
+ pg = alloc_domheap_page(NULL, MEMF_node(domain_to_node(d)));
+ if ( !pg )
+ return -ENOMEM;
+ clear_domain_page(page_to_mfn(pg));
+ d->arch.perdomain_l2_pg[ARG_XLAT_SLOT] = pg;
+
+ l3tab = __map_domain_page(d->arch.perdomain_l3_pg);
+ l3tab[l3_table_offset(ARG_XLAT_VIRT_START)] =
+ l3e_from_page(pg, __PAGE_HYPERVISOR);
+ unmap_domain_page(l3tab);
+ }
+
+ BUILD_BUG_ON((MAX_VIRT_CPUS << ARG_XLAT_VA_SHIFT) >
+ (PERDOMAIN_SLOT_MBYTES << 20));
+
+ if ( !d->arch.arg_xlat_l1_pg )
+ d->arch.arg_xlat_l1_pg = xzalloc_array(struct page_info *,
+ PFN_UP(MAX_VIRT_CPUS <<
+ ARG_XLAT_VA_SHIFT));
+ if ( !d->arch.arg_xlat_l1_pg )
+ return -ENOMEM;
+
+ idx = l2_table_offset(ARG_XLAT_START(v));
+ if ( !d->arch.arg_xlat_l1_pg[idx] )
+ {
+ l2_pgentry_t *l2tab;
+
+ pg = alloc_domheap_page(NULL, MEMF_node(domain_to_node(d)));
+ if ( !pg )
+ return -ENOMEM;
+ clear_domain_page(page_to_mfn(pg));
+ d->arch.arg_xlat_l1_pg[idx] = pg;
+
+ l2tab = __map_domain_page(d->arch.perdomain_l2_pg[ARG_XLAT_SLOT]);
+ l2tab[idx] = l2e_from_page(pg, __PAGE_HYPERVISOR);
+ unmap_domain_page(l2tab);
+ }
- v->arch.compat_arg_xlat = alloc_xenheap_pages(order,
- MEMF_node(vcpu_to_node(v)));
+ l1tab = __map_domain_page(d->arch.arg_xlat_l1_pg[idx]);
+ idx = l1_table_offset(ARG_XLAT_START(v));
+ BUILD_BUG_ON(COMPAT_ARG_XLAT_SIZE > (1UL << ARG_XLAT_VA_SHIFT));
+ for ( i = 0; i < PFN_UP(COMPAT_ARG_XLAT_SIZE); ++i )
+ {
+ pg = alloc_domheap_page(NULL, MEMF_node(domain_to_node(d)));
+ if ( !pg )
+ return -ENOMEM;
+ l1tab[idx + i] = l1e_from_page(pg, __PAGE_HYPERVISOR);
+ }
+ unmap_domain_page(l1tab);
- return v->arch.compat_arg_xlat ? 0 : -ENOMEM;
+ return 0;
}
void free_compat_arg_xlat(struct vcpu *v)
{
- unsigned int order = get_order_from_bytes(COMPAT_ARG_XLAT_SIZE);
+ struct domain *d = v->domain;
+ unsigned long start = ARG_XLAT_START(v);
+ unsigned long va = start + COMPAT_ARG_XLAT_SIZE - 1;
+ l1_pgentry_t *l1tab =
+ __map_domain_page(d->arch.arg_xlat_l1_pg[l2_table_offset(start)]);
+
+ do {
+ l1_pgentry_t l1e = l1tab[l1_table_offset(va)];
+
+ if ( l1e_get_flags(l1e) & _PAGE_PRESENT )
+ {
+ struct page_info *pg = l1e_get_page(l1e);
+
+ l1tab[l1_table_offset(va)] = l1e_empty();
+ flush_tlb_one_mask(d->domain_dirty_cpumask, va);
+ free_domheap_page(pg);
+ }
+ va -= PAGE_SIZE;
+ } while ( va >= start );
- free_xenheap_pages(v->arch.compat_arg_xlat, order);
- v->arch.compat_arg_xlat = NULL;
+ unmap_domain_page(l1tab);
}
void cleanup_frame_table(struct mem_hotadd_info *info)
--- a/xen/include/asm-x86/config.h
+++ b/xen/include/asm-x86/config.h
@@ -212,7 +212,7 @@ extern unsigned char boot_edid_info[128]
/* Slot 260: per-domain mappings (including map cache). */
#define PERDOMAIN_VIRT_START (PML4_ADDR(260))
#define PERDOMAIN_SLOT_MBYTES (PML4_ENTRY_BYTES >> (20 + PAGETABLE_ORDER))
-#define PERDOMAIN_SLOTS 2
+#define PERDOMAIN_SLOTS 3
#define PERDOMAIN_VIRT_SLOT(s) (PERDOMAIN_VIRT_START + (s) * \
(PERDOMAIN_SLOT_MBYTES << 20))
/* Slot 261: machine-to-phys conversion table (256GB). */
@@ -304,6 +304,14 @@ extern unsigned long xen_phys_start;
#define LDT_VIRT_START(v) \
(GDT_VIRT_START(v) + (64*1024))
+/* Argument translation area. The 2nd to last per-domain-mapping sub-area. */
+#define ARG_XLAT_SLOT (PERDOMAIN_SLOTS - 2)
+/* Allow for at least one guard page (COMPAT_ARG_XLAT_SIZE being 2 pages): */
+#define ARG_XLAT_VA_SHIFT (2 + PAGE_SHIFT)
+#define ARG_XLAT_VIRT_START PERDOMAIN_VIRT_SLOT(ARG_XLAT_SLOT)
+#define ARG_XLAT_START(v) \
+ (ARG_XLAT_VIRT_START + ((v)->vcpu_id << ARG_XLAT_VA_SHIFT))
+
/* map_domain_page() map cache. The last per-domain-mapping sub-area. */
#define MAPCACHE_VCPU_ENTRIES (CONFIG_PAGING_LEVELS * CONFIG_PAGING_LEVELS)
#define MAPCACHE_ENTRIES (MAX_VIRT_CPUS * MAPCACHE_VCPU_ENTRIES)
@@ -313,7 +321,7 @@ extern unsigned long xen_phys_start;
MAPCACHE_ENTRIES * PAGE_SIZE)
#define PDPT_L1_ENTRIES \
- ((PERDOMAIN_VIRT_SLOT(PERDOMAIN_SLOTS - 1) - PERDOMAIN_VIRT_START) >> PAGE_SHIFT)
+ ((PERDOMAIN_VIRT_SLOT(PERDOMAIN_SLOTS - 2) - PERDOMAIN_VIRT_START) >> PAGE_SHIFT)
#define PDPT_L2_ENTRIES \
((PDPT_L1_ENTRIES + (1 << PAGETABLE_ORDER) - 1) >> PAGETABLE_ORDER)
--- a/xen/include/asm-x86/domain.h
+++ b/xen/include/asm-x86/domain.h
@@ -244,6 +244,7 @@ struct arch_domain
void **perdomain_pts;
struct page_info *perdomain_l2_pg[PERDOMAIN_SLOTS];
struct page_info *perdomain_l3_pg;
+ struct page_info **arg_xlat_l1_pg;
unsigned int hv_compat_vstart;
@@ -448,9 +449,6 @@ struct arch_vcpu
/* A secondary copy of the vcpu time info. */
XEN_GUEST_HANDLE(vcpu_time_info_t) time_info_guest;
-
- void *compat_arg_xlat;
-
} __cacheline_aligned;
/* Shorthands to improve code legibility. */
--- a/xen/include/asm-x86/x86_64/uaccess.h
+++ b/xen/include/asm-x86/x86_64/uaccess.h
@@ -1,16 +1,15 @@
#ifndef __X86_64_UACCESS_H
#define __X86_64_UACCESS_H
-#define COMPAT_ARG_XLAT_VIRT_BASE compat_arg_xlat_virt_base()
+#define COMPAT_ARG_XLAT_VIRT_BASE ((void *)ARG_XLAT_START(current))
#define COMPAT_ARG_XLAT_SIZE (2*PAGE_SIZE)
struct vcpu;
-void *compat_arg_xlat_virt_base(void);
int setup_compat_arg_xlat(struct vcpu *v);
void free_compat_arg_xlat(struct vcpu *v);
#define is_compat_arg_xlat_range(addr, size) ({ \
unsigned long __off; \
__off = (unsigned long)(addr) - (unsigned long)COMPAT_ARG_XLAT_VIRT_BASE; \
- (__off <= COMPAT_ARG_XLAT_SIZE) && \
+ (__off < COMPAT_ARG_XLAT_SIZE) && \
((__off + (unsigned long)(size)) <= COMPAT_ARG_XLAT_SIZE); \
})
[-- Attachment #3: Type: text/plain, Size: 126 bytes --]
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^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] x86: rework hypercall argument translation area setup
2013-02-21 11:42 [PATCH] x86: rework hypercall argument translation area setup Jan Beulich
@ 2013-02-21 12:08 ` Keir Fraser
2013-02-21 12:26 ` Jan Beulich
0 siblings, 1 reply; 6+ messages in thread
From: Keir Fraser @ 2013-02-21 12:08 UTC (permalink / raw)
To: Jan Beulich, xen-devel
On 21/02/2013 11:42, "Jan Beulich" <JBeulich@suse.com> wrote:
> Rather than using an order-1 Xen heap allocation, use (currently 2)
> individual domain heap pages to populate space in the per-domain
> mapping area.
>
> Also fix an off-by-one mistake in is_compat_arg_xlat_range().
>
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
Well, fine in principle. This manual setup/teardown of l2/l1 pagetables in
the perdomain area is getting a bit tiresome though isn't it? Isn't there
some setup helper that could be abstracted out for all users, and perhaps
even some automated teardown-and-freeing on domain destroy? I just sighed
when I saw more skanky pagetable manipulation for what is a conceptually
simple change.
-- Keir
> --- a/xen/arch/x86/domain.c
> +++ b/xen/arch/x86/domain.c
> @@ -642,6 +642,14 @@ void arch_domain_destroy(struct domain *
> free_domheap_page(d->arch.perdomain_l2_pg[i]);
> free_domheap_page(d->arch.perdomain_l3_pg);
>
> + if ( d->arch.arg_xlat_l1_pg )
> + {
> + for ( i = 0; i < PFN_UP(MAX_VIRT_CPUS << ARG_XLAT_VA_SHIFT); ++i )
> + if ( d->arch.arg_xlat_l1_pg[i] )
> + free_domheap_page(d->arch.arg_xlat_l1_pg[i]);
> + xfree(d->arch.arg_xlat_l1_pg);
> + }
> +
> free_xenheap_page(d->shared_info);
> cleanup_domain_irq_mapping(d);
> }
> --- a/xen/arch/x86/usercopy.c
> +++ b/xen/arch/x86/usercopy.c
> @@ -6,8 +6,8 @@
> * Copyright 2002 Andi Kleen <ak@suse.de>
> */
>
> -#include <xen/config.h>
> #include <xen/lib.h>
> +#include <xen/sched.h>
> #include <asm/uaccess.h>
>
> unsigned long __copy_to_user_ll(void __user *to, const void *from, unsigned
> n)
> --- a/xen/arch/x86/x86_64/mm.c
> +++ b/xen/arch/x86/x86_64/mm.c
> @@ -832,27 +832,93 @@ void __init zap_low_mappings(void)
> __PAGE_HYPERVISOR);
> }
>
> -void *compat_arg_xlat_virt_base(void)
> -{
> - return current->arch.compat_arg_xlat;
> -}
> -
> int setup_compat_arg_xlat(struct vcpu *v)
> {
> - unsigned int order = get_order_from_bytes(COMPAT_ARG_XLAT_SIZE);
> + struct domain *d = v->domain;
> + struct page_info *pg;
> + unsigned int idx, i;
> + l1_pgentry_t *l1tab;
> +
> + if ( !d->arch.perdomain_l2_pg[ARG_XLAT_SLOT] )
> + {
> + l3_pgentry_t *l3tab;
> +
> + pg = alloc_domheap_page(NULL, MEMF_node(domain_to_node(d)));
> + if ( !pg )
> + return -ENOMEM;
> + clear_domain_page(page_to_mfn(pg));
> + d->arch.perdomain_l2_pg[ARG_XLAT_SLOT] = pg;
> +
> + l3tab = __map_domain_page(d->arch.perdomain_l3_pg);
> + l3tab[l3_table_offset(ARG_XLAT_VIRT_START)] =
> + l3e_from_page(pg, __PAGE_HYPERVISOR);
> + unmap_domain_page(l3tab);
> + }
> +
> + BUILD_BUG_ON((MAX_VIRT_CPUS << ARG_XLAT_VA_SHIFT) >
> + (PERDOMAIN_SLOT_MBYTES << 20));
> +
> + if ( !d->arch.arg_xlat_l1_pg )
> + d->arch.arg_xlat_l1_pg = xzalloc_array(struct page_info *,
> + PFN_UP(MAX_VIRT_CPUS <<
> + ARG_XLAT_VA_SHIFT));
> + if ( !d->arch.arg_xlat_l1_pg )
> + return -ENOMEM;
> +
> + idx = l2_table_offset(ARG_XLAT_START(v));
> + if ( !d->arch.arg_xlat_l1_pg[idx] )
> + {
> + l2_pgentry_t *l2tab;
> +
> + pg = alloc_domheap_page(NULL, MEMF_node(domain_to_node(d)));
> + if ( !pg )
> + return -ENOMEM;
> + clear_domain_page(page_to_mfn(pg));
> + d->arch.arg_xlat_l1_pg[idx] = pg;
> +
> + l2tab = __map_domain_page(d->arch.perdomain_l2_pg[ARG_XLAT_SLOT]);
> + l2tab[idx] = l2e_from_page(pg, __PAGE_HYPERVISOR);
> + unmap_domain_page(l2tab);
> + }
>
> - v->arch.compat_arg_xlat = alloc_xenheap_pages(order,
> -
> MEMF_node(vcpu_to_node(v)));
> + l1tab = __map_domain_page(d->arch.arg_xlat_l1_pg[idx]);
> + idx = l1_table_offset(ARG_XLAT_START(v));
> + BUILD_BUG_ON(COMPAT_ARG_XLAT_SIZE > (1UL << ARG_XLAT_VA_SHIFT));
> + for ( i = 0; i < PFN_UP(COMPAT_ARG_XLAT_SIZE); ++i )
> + {
> + pg = alloc_domheap_page(NULL, MEMF_node(domain_to_node(d)));
> + if ( !pg )
> + return -ENOMEM;
> + l1tab[idx + i] = l1e_from_page(pg, __PAGE_HYPERVISOR);
> + }
> + unmap_domain_page(l1tab);
>
> - return v->arch.compat_arg_xlat ? 0 : -ENOMEM;
> + return 0;
> }
>
> void free_compat_arg_xlat(struct vcpu *v)
> {
> - unsigned int order = get_order_from_bytes(COMPAT_ARG_XLAT_SIZE);
> + struct domain *d = v->domain;
> + unsigned long start = ARG_XLAT_START(v);
> + unsigned long va = start + COMPAT_ARG_XLAT_SIZE - 1;
> + l1_pgentry_t *l1tab =
> + __map_domain_page(d->arch.arg_xlat_l1_pg[l2_table_offset(start)]);
> +
> + do {
> + l1_pgentry_t l1e = l1tab[l1_table_offset(va)];
> +
> + if ( l1e_get_flags(l1e) & _PAGE_PRESENT )
> + {
> + struct page_info *pg = l1e_get_page(l1e);
> +
> + l1tab[l1_table_offset(va)] = l1e_empty();
> + flush_tlb_one_mask(d->domain_dirty_cpumask, va);
> + free_domheap_page(pg);
> + }
> + va -= PAGE_SIZE;
> + } while ( va >= start );
>
> - free_xenheap_pages(v->arch.compat_arg_xlat, order);
> - v->arch.compat_arg_xlat = NULL;
> + unmap_domain_page(l1tab);
> }
>
> void cleanup_frame_table(struct mem_hotadd_info *info)
> --- a/xen/include/asm-x86/config.h
> +++ b/xen/include/asm-x86/config.h
> @@ -212,7 +212,7 @@ extern unsigned char boot_edid_info[128]
> /* Slot 260: per-domain mappings (including map cache). */
> #define PERDOMAIN_VIRT_START (PML4_ADDR(260))
> #define PERDOMAIN_SLOT_MBYTES (PML4_ENTRY_BYTES >> (20 + PAGETABLE_ORDER))
> -#define PERDOMAIN_SLOTS 2
> +#define PERDOMAIN_SLOTS 3
> #define PERDOMAIN_VIRT_SLOT(s) (PERDOMAIN_VIRT_START + (s) * \
> (PERDOMAIN_SLOT_MBYTES << 20))
> /* Slot 261: machine-to-phys conversion table (256GB). */
> @@ -304,6 +304,14 @@ extern unsigned long xen_phys_start;
> #define LDT_VIRT_START(v) \
> (GDT_VIRT_START(v) + (64*1024))
>
> +/* Argument translation area. The 2nd to last per-domain-mapping sub-area. */
> +#define ARG_XLAT_SLOT (PERDOMAIN_SLOTS - 2)
> +/* Allow for at least one guard page (COMPAT_ARG_XLAT_SIZE being 2 pages): */
> +#define ARG_XLAT_VA_SHIFT (2 + PAGE_SHIFT)
> +#define ARG_XLAT_VIRT_START PERDOMAIN_VIRT_SLOT(ARG_XLAT_SLOT)
> +#define ARG_XLAT_START(v) \
> + (ARG_XLAT_VIRT_START + ((v)->vcpu_id << ARG_XLAT_VA_SHIFT))
> +
> /* map_domain_page() map cache. The last per-domain-mapping sub-area. */
> #define MAPCACHE_VCPU_ENTRIES (CONFIG_PAGING_LEVELS *
> CONFIG_PAGING_LEVELS)
> #define MAPCACHE_ENTRIES (MAX_VIRT_CPUS * MAPCACHE_VCPU_ENTRIES)
> @@ -313,7 +321,7 @@ extern unsigned long xen_phys_start;
> MAPCACHE_ENTRIES * PAGE_SIZE)
>
> #define PDPT_L1_ENTRIES \
> - ((PERDOMAIN_VIRT_SLOT(PERDOMAIN_SLOTS - 1) - PERDOMAIN_VIRT_START) >>
> PAGE_SHIFT)
> + ((PERDOMAIN_VIRT_SLOT(PERDOMAIN_SLOTS - 2) - PERDOMAIN_VIRT_START) >>
> PAGE_SHIFT)
> #define PDPT_L2_ENTRIES \
> ((PDPT_L1_ENTRIES + (1 << PAGETABLE_ORDER) - 1) >> PAGETABLE_ORDER)
>
> --- a/xen/include/asm-x86/domain.h
> +++ b/xen/include/asm-x86/domain.h
> @@ -244,6 +244,7 @@ struct arch_domain
> void **perdomain_pts;
> struct page_info *perdomain_l2_pg[PERDOMAIN_SLOTS];
> struct page_info *perdomain_l3_pg;
> + struct page_info **arg_xlat_l1_pg;
>
> unsigned int hv_compat_vstart;
>
> @@ -448,9 +449,6 @@ struct arch_vcpu
>
> /* A secondary copy of the vcpu time info. */
> XEN_GUEST_HANDLE(vcpu_time_info_t) time_info_guest;
> -
> - void *compat_arg_xlat;
> -
> } __cacheline_aligned;
>
> /* Shorthands to improve code legibility. */
> --- a/xen/include/asm-x86/x86_64/uaccess.h
> +++ b/xen/include/asm-x86/x86_64/uaccess.h
> @@ -1,16 +1,15 @@
> #ifndef __X86_64_UACCESS_H
> #define __X86_64_UACCESS_H
>
> -#define COMPAT_ARG_XLAT_VIRT_BASE compat_arg_xlat_virt_base()
> +#define COMPAT_ARG_XLAT_VIRT_BASE ((void *)ARG_XLAT_START(current))
> #define COMPAT_ARG_XLAT_SIZE (2*PAGE_SIZE)
> struct vcpu;
> -void *compat_arg_xlat_virt_base(void);
> int setup_compat_arg_xlat(struct vcpu *v);
> void free_compat_arg_xlat(struct vcpu *v);
> #define is_compat_arg_xlat_range(addr, size) ({
> \
> unsigned long __off;
> \
> __off = (unsigned long)(addr) - (unsigned long)COMPAT_ARG_XLAT_VIRT_BASE;
> \
> - (__off <= COMPAT_ARG_XLAT_SIZE) &&
> \
> + (__off < COMPAT_ARG_XLAT_SIZE) &&
> \
> ((__off + (unsigned long)(size)) <= COMPAT_ARG_XLAT_SIZE);
> \
> })
>
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org
> http://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] x86: rework hypercall argument translation area setup
2013-02-21 12:08 ` Keir Fraser
@ 2013-02-21 12:26 ` Jan Beulich
2013-02-21 12:57 ` Keir Fraser
0 siblings, 1 reply; 6+ messages in thread
From: Jan Beulich @ 2013-02-21 12:26 UTC (permalink / raw)
To: Keir Fraser; +Cc: xen-devel
>>> On 21.02.13 at 13:08, Keir Fraser <keir@xen.org> wrote:
> On 21/02/2013 11:42, "Jan Beulich" <JBeulich@suse.com> wrote:
>
>> Rather than using an order-1 Xen heap allocation, use (currently 2)
>> individual domain heap pages to populate space in the per-domain
>> mapping area.
>>
>> Also fix an off-by-one mistake in is_compat_arg_xlat_range().
>>
>> Signed-off-by: Jan Beulich <jbeulich@suse.com>
>
> Well, fine in principle. This manual setup/teardown of l2/l1 pagetables in
> the perdomain area is getting a bit tiresome though isn't it? Isn't there
> some setup helper that could be abstracted out for all users, and perhaps
> even some automated teardown-and-freeing on domain destroy? I just sighed
> when I saw more skanky pagetable manipulation for what is a conceptually
> simple change.
I tried to spot pieces worth folding into helper functions, but
didn't really find anything worthwhile (the purposes of the
mappings are just too different). Perhaps we could have a
map_pages_to_guest(), taking care of all intermediate page
table levels? I can't see much else, and the main problem is that
of tracking pages used for page tables here anyway.
Are we concerned about the performance of guest GDT/LDT page
(un)mappings?
Jan
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] x86: rework hypercall argument translation area setup
2013-02-21 12:26 ` Jan Beulich
@ 2013-02-21 12:57 ` Keir Fraser
2013-02-21 13:05 ` Jan Beulich
0 siblings, 1 reply; 6+ messages in thread
From: Keir Fraser @ 2013-02-21 12:57 UTC (permalink / raw)
To: Jan Beulich; +Cc: xen-devel
On 21/02/2013 12:26, "Jan Beulich" <JBeulich@suse.com> wrote:
>> Well, fine in principle. This manual setup/teardown of l2/l1 pagetables in
>> the perdomain area is getting a bit tiresome though isn't it? Isn't there
>> some setup helper that could be abstracted out for all users, and perhaps
>> even some automated teardown-and-freeing on domain destroy? I just sighed
>> when I saw more skanky pagetable manipulation for what is a conceptually
>> simple change.
>
> I tried to spot pieces worth folding into helper functions, but
> didn't really find anything worthwhile (the purposes of the
> mappings are just too different). Perhaps we could have a
> map_pages_to_guest(), taking care of all intermediate page
> table levels? I can't see much else, and the main problem is that
> of tracking pages used for page tables here anyway.
Well, possibly even that might be an improvement.
> Are we concerned about the performance of guest GDT/LDT page
> (un)mappings?
LDT must often change on guest process context switch? So I would think yes
we do.
-- Keir
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] x86: rework hypercall argument translation area setup
2013-02-21 12:57 ` Keir Fraser
@ 2013-02-21 13:05 ` Jan Beulich
2013-02-21 13:12 ` Keir Fraser
0 siblings, 1 reply; 6+ messages in thread
From: Jan Beulich @ 2013-02-21 13:05 UTC (permalink / raw)
To: Keir Fraser; +Cc: xen-devel
>>> On 21.02.13 at 13:57, Keir Fraser <keir.xen@gmail.com> wrote:
> On 21/02/2013 12:26, "Jan Beulich" <JBeulich@suse.com> wrote:
>> Are we concerned about the performance of guest GDT/LDT page
>> (un)mappings?
>
> LDT must often change on guest process context switch? So I would think yes
> we do.
Linux doesn't normally use an LDT (i.e. only exotic processes
would have one of non-zero size).
Jan
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] x86: rework hypercall argument translation area setup
2013-02-21 13:05 ` Jan Beulich
@ 2013-02-21 13:12 ` Keir Fraser
0 siblings, 0 replies; 6+ messages in thread
From: Keir Fraser @ 2013-02-21 13:12 UTC (permalink / raw)
To: Jan Beulich; +Cc: xen-devel
On 21/02/2013 13:05, "Jan Beulich" <JBeulich@suse.com> wrote:
>>>> On 21.02.13 at 13:57, Keir Fraser <keir.xen@gmail.com> wrote:
>> On 21/02/2013 12:26, "Jan Beulich" <JBeulich@suse.com> wrote:
>>> Are we concerned about the performance of guest GDT/LDT page
>>> (un)mappings?
>>
>> LDT must often change on guest process context switch? So I would think yes
>> we do.
>
> Linux doesn't normally use an LDT (i.e. only exotic processes
> would have one of non-zero size).
That being the case, we probably don't care so much.
-- Keir
> Jan
>
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2013-02-21 13:12 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2013-02-21 11:42 [PATCH] x86: rework hypercall argument translation area setup Jan Beulich
2013-02-21 12:08 ` Keir Fraser
2013-02-21 12:26 ` Jan Beulich
2013-02-21 12:57 ` Keir Fraser
2013-02-21 13:05 ` Jan Beulich
2013-02-21 13:12 ` Keir Fraser
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