lkml.org 
[lkml]   [2012]   [Mar]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH 02/13] KVM: MMU: abstract spte write-protect
Introduce a common function to abstract spte write-protect to cleanup the
code

Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
---
arch/x86/kvm/mmu.c | 57 ++++++++++++++++++++++++++++++---------------------
1 files changed, 33 insertions(+), 24 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index c759e4f..ad40647 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1015,27 +1015,43 @@ static void drop_spte(struct kvm *kvm, u64 *sptep)
rmap_remove(kvm, sptep);
}

+/* Return true if the spte is dropped. */
+static bool spte_write_protect(struct kvm *kvm, u64 *sptep, bool large,
+ int *flush)
+{
+ u64 spte = *sptep;
+
+ if (!is_writable_pte(spte))
+ return false;
+
+ *flush |= true;
+
+ if (large) {
+ pgprintk("rmap_write_protect(large): spte %p %llx\n",
+ spte, *spte);
+ BUG_ON(!is_large_pte(spte));
+
+ drop_spte(kvm, sptep);
+ --kvm->stat.lpages;
+ return true;
+ }
+
+ rmap_printk("rmap_write_protect: spte %p %llx\n", spte, *spte);
+ spte = spte & ~PT_WRITABLE_MASK;
+ mmu_spte_update(sptep, spte);
+
+ return false;
+}
+
static int __rmap_write_protect(struct kvm *kvm, unsigned long *rmapp, int level)
{
u64 *spte = NULL;
int write_protected = 0;

while ((spte = rmap_next(rmapp, spte))) {
- rmap_printk("rmap_write_protect: spte %p %llx\n", spte, *spte);
-
- if (!is_writable_pte(*spte))
- continue;
-
- if (level == PT_PAGE_TABLE_LEVEL) {
- mmu_spte_update(spte, *spte & ~PT_WRITABLE_MASK);
- } else {
- BUG_ON(!is_large_pte(*spte));
- drop_spte(kvm, spte);
- --kvm->stat.lpages;
+ if (spte_write_protect(kvm, spte, level > PT_PAGE_TABLE_LEVEL,
+ &write_protected))
spte = NULL;
- }
-
- write_protected = 1;
}

return write_protected;
@@ -3858,6 +3874,7 @@ int kvm_mmu_setup(struct kvm_vcpu *vcpu)
void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot)
{
struct kvm_mmu_page *sp;
+ int flush = 0;

list_for_each_entry(sp, &kvm->arch.active_mmu_pages, link) {
int i;
@@ -3872,16 +3889,8 @@ void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot)
!is_last_spte(pt[i], sp->role.level))
continue;

- if (is_large_pte(pt[i])) {
- drop_spte(kvm, &pt[i]);
- --kvm->stat.lpages;
- continue;
- }
-
- /* avoid RMW */
- if (is_writable_pte(pt[i]))
- mmu_spte_update(&pt[i],
- pt[i] & ~PT_WRITABLE_MASK);
+ spte_write_protect(kvm, &pt[i],
+ is_large_pte(pt[i]), &flush);
}
}
kvm_flush_remote_tlbs(kvm);
--
1.7.7.6


\
 
 \ /
  Last update: 2012-03-29 11:25    [W:0.294 / U:0.036 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site