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KVM: MMU: Add rmap_next(), a helper for walking kvm rmaps

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Signed-off-by: Izik Eidus <izike@qumranet.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
This commit is contained in:
Izik Eidus 2007-10-16 14:42:30 +02:00 committed by Avi Kivity
parent b284be5764
commit 98348e9507
1 changed files with 35 additions and 10 deletions
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45
drivers/kvm/mmu.c
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@ -456,28 +456,53 @@ static void rmap_remove(struct kvm *kvm, u64 *spte)
}
}
static void rmap_write_protect(struct kvm *kvm, u64 gfn)
static u64 *rmap_next(struct kvm *kvm, unsigned long *rmapp, u64 *spte)
{
struct kvm_rmap_desc *desc;
struct kvm_rmap_desc *prev_desc;
u64 *prev_spte;
int i;
if (!*rmapp)
return NULL;
else if (!(*rmapp & 1)) {
if (!spte)
return (u64 *)*rmapp;
return NULL;
}
desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
prev_desc = NULL;
prev_spte = NULL;
while (desc) {
for (i = 0; i < RMAP_EXT && desc->shadow_ptes[i]; ++i) {
if (prev_spte == spte)
return desc->shadow_ptes[i];
prev_spte = desc->shadow_ptes[i];
}
desc = desc->more;
}
return NULL;
}
static void rmap_write_protect(struct kvm *kvm, u64 gfn)
{
unsigned long *rmapp;
u64 *spte;
u64 *prev_spte;
gfn = unalias_gfn(kvm, gfn);
rmapp = gfn_to_rmap(kvm, gfn);
while (*rmapp) {
if (!(*rmapp & 1))
spte = (u64 *)*rmapp;
else {
desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
spte = desc->shadow_ptes[0];
}
spte = rmap_next(kvm, rmapp, NULL);
while (spte) {
BUG_ON(!spte);
BUG_ON(!(*spte & PT_PRESENT_MASK));
BUG_ON(!(*spte & PT_WRITABLE_MASK));
rmap_printk("rmap_write_protect: spte %p %llx\n", spte, *spte);
rmap_remove(kvm, spte);
set_shadow_pte(spte, *spte & ~PT_WRITABLE_MASK);
prev_spte = spte;
spte = rmap_next(kvm, rmapp, spte);
rmap_remove(kvm, prev_spte);
set_shadow_pte(prev_spte, *prev_spte & ~PT_WRITABLE_MASK);
kvm_flush_remote_tlbs(kvm);
}
}