[PATCH 31/33] KVM: MMU: Flush guest tlb when reducing permissions on a pte

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



If we reduce permissions on a pte, we must flush the cached copy of the pte
from the guest's tlb.

This is implemented at the moment by flushing the entire guest tlb, and can
be improved by flushing just the relevant virtual address, if it is known.

Signed-off-by: Avi Kivity <[email protected]>

Index: linux-2.6/drivers/kvm/mmu.c
===================================================================
--- linux-2.6.orig/drivers/kvm/mmu.c
+++ linux-2.6/drivers/kvm/mmu.c
@@ -383,6 +383,7 @@ static void rmap_write_protect(struct kv
 		BUG_ON(!(*spte & PT_WRITABLE_MASK));
 		rmap_printk("rmap_write_protect: spte %p %llx\n", spte, *spte);
 		rmap_remove(vcpu, spte);
+		kvm_arch_ops->tlb_flush(vcpu);
 		*spte &= ~(u64)PT_WRITABLE_MASK;
 	}
 }
@@ -594,6 +595,7 @@ static void kvm_mmu_page_unlink_children
 				rmap_remove(vcpu, &pt[i]);
 			pt[i] = 0;
 		}
+		kvm_arch_ops->tlb_flush(vcpu);
 		return;
 	}
 
@@ -927,7 +929,10 @@ static inline void set_pte_common(struct
 			pgprintk("%s: found shadow page for %lx, marking ro\n",
 				 __FUNCTION__, gfn);
 			access_bits &= ~PT_WRITABLE_MASK;
-			*shadow_pte &= ~PT_WRITABLE_MASK;
+			if (is_writeble_pte(*shadow_pte)) {
+				    *shadow_pte &= ~PT_WRITABLE_MASK;
+				    kvm_arch_ops->tlb_flush(vcpu);
+			}
 		}
 	}
 
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux