On Tue, May 29, 2012 at 02:49:14PM +0800, Xiao Guangrong wrote: > This bit indicates whether the spte can be writable on MMU, that means > the corresponding gpte is writable and the corresponding gfn is not > protected by shadow page protection > > Signed-off-by: Xiao Guangrong <[email protected]> > --- > arch/x86/kvm/mmu.c | 41 +++++++++++++++++++++++++++-------------- > 1 files changed, 27 insertions(+), 14 deletions(-) > > diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c > index 4810992..150c5ad 100644 > --- a/arch/x86/kvm/mmu.c > +++ b/arch/x86/kvm/mmu.c > @@ -145,7 +145,8 @@ module_param(dbg, bool, 0644); > #define CREATE_TRACE_POINTS > #include "mmutrace.h" > > -#define SPTE_HOST_WRITEABLE (1ULL << PT_FIRST_AVAIL_BITS_SHIFT) > +#define SPTE_HOST_WRITEABLE (1ULL << PT_FIRST_AVAIL_BITS_SHIFT) > +#define SPTE_MMU_WRITEABLE (1ULL << (PT_FIRST_AVAIL_BITS_SHIFT + 1)) > > #define SHADOW_PT_INDEX(addr, level) PT64_INDEX(addr, level) > > @@ -1065,32 +1066,43 @@ static void drop_spte(struct kvm *kvm, u64 *sptep) > rmap_remove(kvm, sptep); > } > > +static bool spte_can_be_writable(u64 spte) > +{ > + return !(~spte & (SPTE_HOST_WRITEABLE | SPTE_MMU_WRITEABLE)); > +} > + > /* Return true if the spte is dropped. */ > -static bool spte_write_protect(struct kvm *kvm, u64 *sptep, bool *flush) > +static bool > +spte_write_protect(struct kvm *kvm, u64 *sptep, bool *flush, bool pt_protect) > { > u64 spte = *sptep; > > - if (!is_writable_pte(spte)) > + if (!is_writable_pte(spte) && > + !(pt_protect && spte_can_be_writable(spte))) > return false; > > rmap_printk("rmap_write_protect: spte %p %llx\n", sptep, *sptep); > > - *flush |= true; > if (is_large_pte(spte)) { > WARN_ON(page_header(__pa(sptep))->role.level == > PT_PAGE_TABLE_LEVEL); > + > + *flush |= true; > drop_spte(kvm, sptep); > --kvm->stat.lpages; > return true; > } > > + if (pt_protect) > + spte &= ~SPTE_MMU_WRITEABLE; > spte = spte & ~PT_WRITABLE_MASK; > - mmu_spte_update(sptep, spte); > + > + *flush = mmu_spte_update(sptep, spte);
This clears previous flush value when looping over multiple sptes in a single rmapp. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
