ia64/xen-unstable

changeset 2651:11aa3dfa5e00

bitkeeper revision 1.1159.113.2 (4171af5bkubQeHmeCV0gipUrBqdltA)

Fix TLB coherency bug in map_domain_mem, as pointed out
by Michael Fetterman.
author kaf24@freefall.cl.cam.ac.uk
date Sat Oct 16 23:31:39 2004 +0000 (2004-10-16)
parents dc59c5558adc
children 756c16a98f27
files xen/arch/x86/x86_32/domain_page.c
line diff
     1.1 --- a/xen/arch/x86/x86_32/domain_page.c	Sat Oct 16 01:39:42 2004 +0000
     1.2 +++ b/xen/arch/x86/x86_32/domain_page.c	Sat Oct 16 23:31:39 2004 +0000
     1.3 @@ -19,7 +19,7 @@
     1.4  #include <asm/flushtlb.h>
     1.5  
     1.6  unsigned long *mapcache;
     1.7 -static unsigned int map_idx, shadow_map_idx[NR_CPUS];
     1.8 +static unsigned int map_idx, epoch, shadow_epoch[NR_CPUS];
     1.9  static spinlock_t map_lock = SPIN_LOCK_UNLOCKED;
    1.10  
    1.11  /* Use a spare PTE bit to mark entries ready for recycling. */
    1.12 @@ -30,11 +30,11 @@ static void flush_all_ready_maps(void)
    1.13      unsigned long *cache = mapcache;
    1.14  
    1.15      /* A bit skanky -- depends on having an aligned PAGE_SIZE set of PTEs. */
    1.16 -    do { if ( (*cache & READY_FOR_TLB_FLUSH) ) *cache = 0; }
    1.17 +    do {
    1.18 +        if ( (*cache & READY_FOR_TLB_FLUSH) )
    1.19 +            *cache = 0;
    1.20 +    }
    1.21      while ( ((unsigned long)(++cache) & ~PAGE_MASK) != 0 );
    1.22 -
    1.23 -    perfc_incrc(domain_page_tlb_flush);
    1.24 -    local_flush_tlb();
    1.25  }
    1.26  
    1.27  
    1.28 @@ -50,25 +50,29 @@ void *map_domain_mem(unsigned long pa)
    1.29      spin_lock_irqsave(&map_lock, flags);
    1.30  
    1.31      /* Has some other CPU caused a wrap? We must flush if so. */
    1.32 -    if ( map_idx < shadow_map_idx[cpu] )
    1.33 +    if ( epoch != shadow_epoch[cpu] )
    1.34      {
    1.35          perfc_incrc(domain_page_tlb_flush);
    1.36          local_flush_tlb();
    1.37 +        shadow_epoch[cpu] = epoch;
    1.38      }
    1.39  
    1.40 -    for ( ; ; )
    1.41 -    {
    1.42 +    do {
    1.43          idx = map_idx = (map_idx + 1) & (MAPCACHE_ENTRIES - 1);
    1.44 -        if ( idx == 0 ) flush_all_ready_maps();
    1.45 -        if ( cache[idx] == 0 ) break;
    1.46 +        if ( unlikely(idx == 0) )
    1.47 +        {
    1.48 +            flush_all_ready_maps();
    1.49 +            perfc_incrc(domain_page_tlb_flush);
    1.50 +            local_flush_tlb();
    1.51 +            shadow_epoch[cpu] = ++epoch;
    1.52 +        }
    1.53      }
    1.54 +    while ( cache[idx] != 0 );
    1.55  
    1.56      cache[idx] = (pa & PAGE_MASK) | __PAGE_HYPERVISOR;
    1.57  
    1.58      spin_unlock_irqrestore(&map_lock, flags);
    1.59  
    1.60 -    shadow_map_idx[cpu] = idx;
    1.61 -
    1.62      va = MAPCACHE_VIRT_START + (idx << PAGE_SHIFT) + (pa & ~PAGE_MASK);
    1.63      return (void *)va;
    1.64  }