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 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
- try to unsynchronize the page
- if successful, we can let the guest continue and modify the gpte
- emulate the instruction
--
1.8.1.4
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