linux-kernel - [136/165] KVM: MMU: invalidate and flush on spte small->large page size change

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Message-Id: <20100730171511.969646411@clark.site>
Date:	Fri, 30 Jul 2010 10:16:04 -0700
From:	Greg KH <gregkh@...e.de>
To:	linux-kernel@...r.kernel.org, stable@...nel.org
Cc:	stable-review@...nel.org, torvalds@...ux-foundation.org,
	akpm@...ux-foundation.org, alan@...rguk.ukuu.org.uk,
	Marcelo Tosatti <mtosatti@...hat.com>,
	Avi Kivity <avi@...hat.com>
Subject: [136/165] KVM: MMU: invalidate and flush on spte small->large page size change

2.6.32-stable review patch.  If anyone has any objections, please let us know.

------------------

Always invalidate spte and flush TLBs when changing page size, to make
sure different sized translations for the same address are never cached
in a CPU's TLB.

Currently the only case where this occurs is when a non-leaf spte pointer is
overwritten by a leaf, large spte entry. This can happen after dirty
logging is disabled on a memslot, for example.

Noticed by Andrea.

KVM-Stable-Tag
Signed-off-by: Marcelo Tosatti <mtosatti@...hat.com>
Signed-off-by: Avi Kivity <avi@...hat.com>
(cherry picked from commit 3be2264be3c00865116f997dc53ebcc90fe7fc4b)
---
 arch/x86/kvm/mmu.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1901,6 +1901,8 @@ static void mmu_set_spte(struct kvm_vcpu
 
 			child = page_header(pte & PT64_BASE_ADDR_MASK);
 			mmu_page_remove_parent_pte(child, sptep);
+			__set_spte(sptep, shadow_trap_nonpresent_pte);
+			kvm_flush_remote_tlbs(vcpu->kvm);
 		} else if (pfn != spte_to_pfn(*sptep)) {
 			pgprintk("hfn old %lx new %lx\n",
 				 spte_to_pfn(*sptep), pfn);


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