Keir Fraser wrote:
On 8 Jun 2006, at 10:48, Mathieu Ropert wrote:
- events/clock issue: there seems to be a race condition leading to
clock not ticking, hence putting system to sleep till a
keyboard/network/disk interrupt is received.
The ticker doesn't tick when you block. Your idle loop needs to
disable interrupts, set a one-shot timer, then block. See safe_halt()
in our Linux source tree (arch/i386/kernel/time-xen.c) -- the function
expects to be called with interrupts disabled and caller should also
have already checked for any other threads being runnable.
-- Keir
I've attached 3 patches needed for OpenBSD/amd64 to work. The two first
address a bug in loadelfsymtab() which load the ELF symbol table at a
bad address on x86_64. More explanations can be found in one of my older
posts.
The third is a first try to fix the issue I have with linear pagetables.
It does fix my issue, and doesn't break my Linux dom0, but besides this
fact, I have no guarantee. Any feedback or advice would be appreciated.
Mathieu
diff -r -bu a/tools/libxc/xc_load_elf.c b/tools/libxc/xc_load_elf.c
--- a/tools/libxc/xc_load_elf.c 2006-06-09 12:32:22.000000000 +0200
+++ b/tools/libxc/xc_load_elf.c 2006-06-09 12:37:04.000000000 +0200
@@ -283,8 +283,9 @@
return 0;
maxva = (dsi->v_kernend + ELFROUND - 1) & ~(ELFROUND - 1);
- symva = maxva;
- maxva += sizeof(int);
+ if (maxva - dsi->v_kernend < sizeof(int))
+ maxva += ELFROUND;
+ symva = maxva - sizeof(int);
dsi->symtab_addr = maxva;
dsi->symtab_len = 0;
maxva += sizeof(Elf_Ehdr) + ehdr->e_shnum * sizeof(Elf_Shdr);
diff -r -bu a/xen/common/elf.c b/xen/common/elf.c
--- a/xen/common/elf.c 2006-06-09 12:32:24.000000000 +0200
+++ b/xen/common/elf.c 2006-06-09 12:36:57.000000000 +0200
@@ -185,8 +185,9 @@
return;
maxva = (dsi->v_kernend + ELFROUND - 1) & ~(ELFROUND - 1);
- symva = maxva;
- maxva += sizeof(int);
+ if (maxva - dsi->v_kernend < sizeof(int))
+ maxva += ELFROUND;
+ symva = maxva - sizeof(int);
dsi->symtab_addr = maxva;
dsi->symtab_len = 0;
maxva += sizeof(Elf_Ehdr) + ehdr->e_shnum * sizeof(Elf_Shdr);
diff -r -bu a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
--- a/xen/arch/x86/mm.c 2006-06-09 12:32:24.000000000 +0200
+++ b/xen/arch/x86/mm.c 2006-06-09 12:41:04.000000000 +0200
@@ -493,7 +493,7 @@
*/
static int
get_linear_pagetable(
- root_pgentry_t re, unsigned long re_pfn, struct domain *d)
+ pgentry_t re, unsigned long re_pfn, struct domain *d, int level)
{
unsigned long x, y;
struct page_info *page;
@@ -501,13 +501,13 @@
ASSERT( !shadow_mode_refcounts(d) );
- if ( (root_get_flags(re) & _PAGE_RW) )
+ if ( (pgentry_get_flags(re, level) & _PAGE_RW) )
{
MEM_LOG("Attempt to create linear p.t. with write perms");
return 0;
}
- if ( (pfn = root_get_pfn(re)) != re_pfn )
+ if ( (pfn = pgentry_get_pfn(re, level)) != re_pfn )
{
/* Make sure the mapped frame belongs to the correct domain. */
if ( unlikely(!get_page_from_pagenr(pfn, d)) )
@@ -522,8 +522,7 @@
do {
x = y;
if ( unlikely((x & PGT_count_mask) == PGT_count_mask) ||
- unlikely((x & (PGT_type_mask|PGT_validated)) !=
- (PGT_root_page_table|PGT_validated)) )
+ unlikely(!(x & PGT_validated) || !is_ptp(x)))
{
put_page(page);
return 0;
@@ -611,9 +610,12 @@
vaddr <<= PGT_va_shift;
rc = get_page_and_type_from_pagenr(
l2e_get_pfn(l2e), PGT_l1_page_table | vaddr, d);
-#if CONFIG_PAGING_LEVELS == 2
- if ( unlikely(!rc) )
- rc = get_linear_pagetable(l2e, pfn, d);
+#if CONFIG_PAGING_LEVELS >= 2
+ if ( unlikely(!rc) ) {
+ pgentry_t re;
+ re.l2.l2 = l2e.l2;
+ rc = get_linear_pagetable(re, pfn, d, 2);
+ }
#endif
return rc;
}
@@ -643,6 +645,13 @@
rc = get_page_and_type_from_pagenr(
l3e_get_pfn(l3e),
PGT_l2_page_table | vaddr, d);
+
+ if ( unlikely(!rc) ) {
+ pgentry_t re;
+ re.l3.l3 = l3e.l3;
+ rc = get_linear_pagetable(re, pfn, d, 3);
+ }
+
return rc;
}
#endif /* 3 level */
@@ -672,8 +681,11 @@
l4e_get_pfn(l4e),
PGT_l3_page_table | vaddr, d);
- if ( unlikely(!rc) )
- rc = get_linear_pagetable(l4e, pfn, d);
+ if ( unlikely(!rc) ) {
+ pgentry_t re;
+ re.l4.l4 = l4e.l4;
+ rc = get_linear_pagetable(re, pfn, d, 4);
+ }
return rc;
}
diff -r -bu a/xen/include/asm-x86/page.h b/xen/include/asm-x86/page.h
--- a/xen/include/asm-x86/page.h 2006-06-09 12:32:24.000000000 +0200
+++ b/xen/include/asm-x86/page.h 2006-06-09 12:44:03.000000000 +0200
@@ -179,6 +179,69 @@
#define pagetable_from_page(pg) pagetable_from_pfn(page_to_mfn(pg))
#define pagetable_from_paddr(p) pagetable_from_pfn((p)>>PAGE_SHIFT)
#define pagetable_null() pagetable_from_pfn(0)
+
+/* Guest linear PT handling */
+typedef union {
+ l1_pgentry_t l1;
+#if CONFIG_PAGING_LEVELS >= 2
+ l2_pgentry_t l2;
+#if CONFIG_PAGING_LEVELS >= 3
+ l3_pgentry_t l3;
+#if CONFIG_PAGING_LEVELS == 4
+ l4_pgentry_t l4;
+#endif /* LEVELS == 4 */
+#endif /* LEVELS >= 3 */
+#endif /* LEVELS >= 2 */
+} pgentry_t;
+
+static inline intpte_t pgentry_get_flags(pgentry_t p, int level)
+{
+ switch (level)
+ {
+ case 1:
+ return l1e_get_flags(p.l1);
+#if CONFIG_PAGING_LEVELS >= 2
+ case 2:
+ return l2e_get_flags(p.l2);
+#if CONFIG_PAGING_LEVELS >= 3
+ case 3:
+ return l3e_get_flags(p.l3);
+#if CONFIG_PAGING_LEVELS == 4
+ case 4:
+ return l4e_get_flags(p.l4);
+#endif /* LEVELS == 4 */
+#endif /* LEVELS >= 3 */
+#endif /* LEVELS >= 2 */
+ default:
+ /* should not happen */
+ return 0;
+ }
+}
+
+static inline intpte_t pgentry_get_pfn(pgentry_t p, int level)
+{
+ switch (level)
+ {
+ case 1:
+ return l1e_get_pfn(p.l1);
+#if CONFIG_PAGING_LEVELS >= 2
+ case 2:
+ return l2e_get_pfn(p.l2);
+#if CONFIG_PAGING_LEVELS >= 3
+ case 3:
+ return l3e_get_pfn(p.l3);
+#if CONFIG_PAGING_LEVELS == 4
+ case 4:
+ return l4e_get_pfn(p.l4);
+#endif /* LEVELS == 4 */
+#endif /* LEVELS >= 3 */
+#endif /* LEVELS >= 2 */
+ default:
+ /* should not happen */
+ return 0;
+ }
+}
+
#endif
#define clear_page(_p) memset((void *)(_p), 0, PAGE_SIZE)
diff -r -bu a/xen/include/asm-x86/x86_32/page-2level.h
b/xen/include/asm-x86/x86_32/page-2level.h
--- a/xen/include/asm-x86/x86_32/page-2level.h 2006-06-09 12:32:24.000000000
+0200
+++ b/xen/include/asm-x86/x86_32/page-2level.h 2006-06-09 12:37:10.000000000
+0200
@@ -28,6 +28,11 @@
#endif /* !__ASSEMBLY__ */
+/* Check if page type is page table (any level) */
+#define is_ptp(x) \
+ ((x & PGT_type_mask) == PGT_l1_page_table \
+ || (x & PGT_type_mask) == PGT_l2_page_table)
+
/* root table */
#define root_get_pfn l2e_get_pfn
#define root_get_flags l2e_get_flags
diff -r -bu a/xen/include/asm-x86/x86_32/page-3level.h
b/xen/include/asm-x86/x86_32/page-3level.h
--- a/xen/include/asm-x86/x86_32/page-3level.h 2006-06-09 12:32:24.000000000
+0200
+++ b/xen/include/asm-x86/x86_32/page-3level.h 2006-06-09 12:37:10.000000000
+0200
@@ -38,6 +38,12 @@
#endif /* !__ASSEMBLY__ */
+/* Check if page type is page table (any level) */
+#define is_ptp(x) \
+ ((x & PGT_type_mask) == PGT_l1_page_table \
+ || (x & PGT_type_mask) == PGT_l2_page_table \
+ || (x & PGT_type_mask) == PGT_l3_page_table)
+
/* root table */
#define root_get_pfn l3e_get_pfn
#define root_get_flags l3e_get_flags
diff -r -bu a/xen/include/asm-x86/x86_64/page.h
b/xen/include/asm-x86/x86_64/page.h
--- a/xen/include/asm-x86/x86_64/page.h 2006-06-09 12:32:24.000000000 +0200
+++ b/xen/include/asm-x86/x86_64/page.h 2006-06-09 12:37:10.000000000 +0200
@@ -41,6 +41,13 @@
#endif /* !__ASSEMBLY__ */
+/* Check if page type is page table (any level) */
+#define is_ptp(x) \
+ ((x & PGT_type_mask) == PGT_l1_page_table \
+ || (x & PGT_type_mask) == PGT_l2_page_table \
+ || (x & PGT_type_mask) == PGT_l3_page_table \
+ || (x & PGT_type_mask) == PGT_l4_page_table)
+
/* Given a virtual address, get an entry offset into a linear page table. */
#define l1_linear_offset(_a) (((_a) & VADDR_MASK) >> L1_PAGETABLE_SHIFT)
#define l2_linear_offset(_a) (((_a) & VADDR_MASK) >> L2_PAGETABLE_SHIFT)
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