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| author | Marc Zyngier <maz@kernel.org> | 2023-01-05 15:25:54 +0000 |
|---|---|---|
| committer | Marc Zyngier <maz@kernel.org> | 2023-01-05 15:25:54 +0000 |
| commit | afbb1b1caef7fb8b23f31f32162dd5756d877dd5 (patch) | |
| tree | 628e6df3305d1c38ba277363bd37b82533da518b /Documentation | |
| parent | d5b4d07bb361fa893244cf55ce5eb053e29b5562 (diff) | |
| parent | b0803ba72b558957fdcfe845939ee788b7ce5919 (diff) | |
| download | linux-afbb1b1caef7fb8b23f31f32162dd5756d877dd5.tar.bz2 | |
Merge branch kvm-arm64/s1ptw-write-fault into kvmarm-master/fixes
* kvm-arm64/s1ptw-write-fault:
: .
: Fix S1PTW fault handling that was until then always taken
: as a write. From the cover letter:
:
: `Recent developments on the EFI front have resulted in guests that
: simply won't boot if the page tables are in a read-only memslot and
: that you're a bit unlucky in the way S2 gets paged in... The core
: issue is related to the fact that we treat a S1PTW as a write, which
: is close enough to what needs to be done. Until to get to RO memslots.
:
: The first patch fixes this and is definitely a stable candidate. It
: splits the faulting of page tables in two steps (RO translation fault,
: followed by a writable permission fault -- should it even happen).
: The second one documents the slightly odd behaviour of PTW writes to
: RO memslot, which do not result in a KVM_MMIO exit. The last patch is
: totally optional, only tangentially related, and randomly repainting
: stuff (maybe that's contagious, who knows)."
:
: .
KVM: arm64: Convert FSC_* over to ESR_ELx_FSC_*
KVM: arm64: Document the behaviour of S1PTW faults on RO memslots
KVM: arm64: Fix S1PTW handling on RO memslots
Signed-off-by: Marc Zyngier <maz@kernel.org>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/virt/kvm/api.rst | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index deb494f759ed..dbed78a9c31b 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -1354,6 +1354,14 @@ the memory region are automatically reflected into the guest. For example, an mmap() that affects the region will be made visible immediately. Another example is madvise(MADV_DROP). +Note: On arm64, a write generated by the page-table walker (to update +the Access and Dirty flags, for example) never results in a +KVM_EXIT_MMIO exit when the slot has the KVM_MEM_READONLY flag. This +is because KVM cannot provide the data that would be written by the +page-table walker, making it impossible to emulate the access. +Instead, an abort (data abort if the cause of the page-table update +was a load or a store, instruction abort if it was an instruction +fetch) is injected in the guest. 4.36 KVM_SET_TSS_ADDR --------------------- |