On 27/08/19 23:40, Sean Christopherson wrote:
> Rework the emulator and its users to handle failure scenarios entirely
> within the emulator.
>
> {x86,kvm}_emulate_instruction() currently returns a tri-state value to
> indicate success/continue, userspace exit needed, and failure. The
> intent of returning EMULATE_FAIL is to let the caller handle failure in
> a manner that is appropriate for the current context. In practice,
> the emulator has ended up with a mixture of failure handling, i.e.
> whether or not the emulator takes action on failure is dependent on the
> specific flavor of emulation.
>
> The mixed handling has proven to be rather fragile, e.g. many flows
> incorrectly assume their specific flavor of emulation cannot fail or
> that the emulator sets state to report the failure back to userspace.
>
> Move everything inside the emulator, piece by piece, so that the
> emulation routines can return '0' for exit to userspace and '1' for
> resume the guest, just like every other VM-Exit handler.
>
> Patch 13/14 is a tangentially related bug fix that conflicts heavily with
> this series, so I tacked it on here.
>
> Patch 14/14 documents the emulation types. I added it as a separate
> patch at the very end so that the comments could reference the final
> state of the code base, e.g. incorporate the rule change for using
> EMULTYPE_SKIP that is introduced in patch 13/14.
>
> v1:
> - https://patchwork.kernel.org/cover/11110331/
>
> v2:
> - Collect reviews. [Vitaly and Liran]
> - Squash VMware emultype changes into a single patch. [Liran]
> - Add comments in VMX/SVM for VMware #GP handling. [Vitaly]
> - Tack on the EPT misconfig bug fix.
> - Add a patch to comment/document the emultypes. [Liran]
>
> Sean Christopherson (14):
> KVM: x86: Relocate MMIO exit stats counting
> KVM: x86: Clean up handle_emulation_failure()
> KVM: x86: Refactor kvm_vcpu_do_singlestep() to remove out param
> KVM: x86: Don't attempt VMWare emulation on #GP with non-zero error
> code
> KVM: x86: Move #GP injection for VMware into x86_emulate_instruction()
> KVM: x86: Add explicit flag for forced emulation on #UD
> KVM: x86: Move #UD injection for failed emulation into emulation code
> KVM: x86: Exit to userspace on emulation skip failure
> KVM: x86: Handle emulation failure directly in kvm_task_switch()
> KVM: x86: Move triple fault request into RM int injection
> KVM: VMX: Remove EMULATE_FAIL handling in handle_invalid_guest_state()
> KVM: x86: Remove emulation_result enums, EMULATE_{DONE,FAIL,USER_EXIT}
> KVM: VMX: Handle single-step #DB for EMULTYPE_SKIP on EPT misconfig
> KVM: x86: Add comments to document various emulation types
>
> arch/x86/include/asm/kvm_host.h | 40 +++++++--
> arch/x86/kvm/mmu.c | 16 +---
> arch/x86/kvm/svm.c | 62 ++++++--------
> arch/x86/kvm/vmx/vmx.c | 147 +++++++++++++-------------------
> arch/x86/kvm/x86.c | 133 ++++++++++++++++-------------
> arch/x86/kvm/x86.h | 2 +-
> 6 files changed, 195 insertions(+), 205 deletions(-)
>
Queued, thanks (a couple conflicts had to be sorted out, but nothing
requiring a respin).
Paolo
