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| author | Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> | 2013-06-19 11:09:22 +0200 |
|---|---|---|
| committer | Gleb Natapov <gleb@redhat.com> | 2013-06-27 13:20:44 +0200 |
| commit | 67652ed34390b19ede6f847d23d8c68e2c819b50 (patch) | |
| tree | e0fbd626e7f812fddbc3ea46fe96cc079fdd7ca8 | |
| parent | KVM: MMU: document write_flooding_count (diff) | |
| download | linux-67652ed34390b19ede6f847d23d8c68e2c819b50.tar.xz linux-67652ed34390b19ede6f847d23d8c68e2c819b50.zip | |
KVM: MMU: document mmio page fault
Document it to Documentation/virtual/kvm/mmu.txt
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| -rw-r--r-- | Documentation/virtual/kvm/mmu.txt | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/Documentation/virtual/kvm/mmu.txt b/Documentation/virtual/kvm/mmu.txt index 0db7743c55e1..0aa8e0e34119 100644 --- a/Documentation/virtual/kvm/mmu.txt +++ b/Documentation/virtual/kvm/mmu.txt @@ -272,14 +272,21 @@ 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 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 - 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 bit on the spte (see callers of kvm_mmu_set_mmio_spte_mask) - try to unsynchronize the page - if successful, we can let the guest continue and modify the gpte - emulate the instruction |