this make the rmap keep reverse mapping on all the present shadow pages
>From 3b5821a55836f82f987b878982cbc6fc8336371f Mon Sep 17 00:00:00 2001
From: Izik Eidus <[EMAIL PROTECTED](none)>
Date: Sat, 13 Oct 2007 01:47:44 +0200
Subject: [PATCH] modify the rmap so it will hold reverse mapping to all present
shadow pages
Signed-off-by: Izik Eidus <[EMAIL PROTECTED]>
---
drivers/kvm/mmu.c | 52 ++++++++++++++++++++++++++++++++++++----------------
1 files changed, 36 insertions(+), 16 deletions(-)
diff --git a/drivers/kvm/mmu.c b/drivers/kvm/mmu.c
index f52604a..cfbeec8 100644
--- a/drivers/kvm/mmu.c
+++ b/drivers/kvm/mmu.c
@@ -211,8 +211,8 @@ static int is_io_pte(unsigned long pte)
static int is_rmap_pte(u64 pte)
{
- return (pte & (PT_WRITABLE_MASK | PT_PRESENT_MASK))
- == (PT_WRITABLE_MASK | PT_PRESENT_MASK);
+ return pte != shadow_trap_nonpresent_pte
+ && pte != shadow_notrap_nonpresent_pte;
}
static void set_shadow_pte(u64 *sptep, u64 spte)
@@ -456,29 +456,51 @@ 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;
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);
+ if (is_writeble_pte(*spte))
+ set_shadow_pte(spte, *spte & ~PT_WRITABLE_MASK);
kvm_flush_remote_tlbs(kvm);
+ spte = rmap_next(kvm, rmapp, spte);
}
}
@@ -1399,10 +1421,8 @@ void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot)
pt = page->spt;
for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
/* avoid RMW */
- if (pt[i] & PT_WRITABLE_MASK) {
- rmap_remove(kvm, &pt[i]);
+ if (pt[i] & PT_WRITABLE_MASK)
pt[i] &= ~PT_WRITABLE_MASK;
- }
}
}
--
1.5.2.4
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