On 06/19/2013 08:10 PM, Paolo Bonzini wrote: > Il 19/06/2013 11:09, Xiao Guangrong ha scritto: >> Document it to Documentation/virtual/kvm/mmu.txt >> >> Signed-off-by: Xiao Guangrong <xiaoguangrong@xxxxxxxxxxxxxxxxxx> >> --- >> Documentation/virtual/kvm/mmu.txt | 11 +++++++++-- >> 1 file changed, 9 insertions(+), 2 deletions(-) >> >> diff --git a/Documentation/virtual/kvm/mmu.txt b/Documentation/virtual/kvm/mmu.txt >> index 5a6b2e2..4fb442b 100644 >> --- a/Documentation/virtual/kvm/mmu.txt >> +++ b/Documentation/virtual/kvm/mmu.txt >> @@ -270,14 +270,21 @@ This is the most complicated event. The cause of a page fault can be: >> >> Handling a page fault is performed as follows: >> >> + - if the RSV bit of the error code is set, the page fault is caused by guest >> + accessing MMIO, walk shadow page table to get the last spte where the mmio >> + information is stored and cache the information to vcpu->arch.mmio_gva, >> + vcpu->arch.access and vcpu->arch.mmio_gfn then call the emulator to emulate >> + the instruction who will get the benefit from the cached mmio info > > + - if the RSV bit of the error code is set, the page fault is caused by guest > + accessing MMIO and cached MMIO information is available. > + - walk shadow page table > + - cache the information to vcpu->arch.mmio_gva, vcpu->arch.access and > + vcpu->arch.mmio_gfn, and call the emulator Nice. > >> - if needed, walk the guest page tables to determine the guest translation >> (gva->gpa or ngpa->gpa) >> - if permissions are insufficient, reflect the fault back to the guest >> - determine the host page >> - - if this is an mmio request, there is no host page; call the emulator >> - to emulate the instruction instead >> + - if this is an mmio request, there is no host page; cache the info to >> + vcpu->arch.mmio_gva, vcpu->arch.access and vcpu->arch.mmio_gfn >> - walk the shadow page table to find the spte for the translation, >> instantiating missing intermediate page tables as necessary >> + - If this is an mmio request, cache the mmio info to the spte and set some >> + reserved bits on the spte > > Added "(see callers of kvm_mmu_set_mmio_spte_mask)". Not really related, but > just came to my mind: perhaps we can have a section on A/D bits too. It is useful i think. Will do it. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
