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authorAvi Kivity <avi@redhat.com>2010-05-27 14:35:58 +0300
committerGreg Kroah-Hartman <gregkh@suse.de>2010-08-02 10:26:44 -0700
commit0c848bde40bcb7e6920c62c8e845d77e90fba27b (patch)
tree7e9238f235a458b396f1e6a2c140a095632937fb /arch
parent59346700ac87134862dc0acd0ab6c9e18cfab577 (diff)
downloadlwn-0c848bde40bcb7e6920c62c8e845d77e90fba27b.tar.gz
lwn-0c848bde40bcb7e6920c62c8e845d77e90fba27b.zip
KVM: MMU: Remove user access when allowing kernel access to gpte.w=0 page
If cr0.wp=0, we have to allow the guest kernel access to a page with pte.w=0. We do that by setting spte.w=1, since the host cr0.wp must remain set so the host can write protect pages. Once we allow write access, we must remove user access otherwise we mistakenly allow the user to write the page. Reviewed-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> Signed-off-by: Avi Kivity <avi@redhat.com> (cherry picked from commit 69325a122580d3a7b26589e8efdd6663001c3297)
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kvm/mmu.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 88220210ed5e..99f646f7c6a4 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1849,6 +1849,9 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
spte |= PT_WRITABLE_MASK;
+ if (!tdp_enabled && !(pte_access & ACC_WRITE_MASK))
+ spte &= ~PT_USER_MASK;
+
/*
* Optimization: for pte sync, if spte was writable the hash
* lookup is unnecessary (and expensive). Write protection