On 23/01/21 00:50, Sean Christopherson wrote:
This is effectively belated feedback on the SEV-ES series. My primary interest is to revert the GPR dirty/available tracking, as it's pure overhead for non-SEV-ES VMs, and even for SEV-ES I suspect the dirty tracking is at best lost in the noise, and possibly even a net negative. My original plan was to submit patches 1+3 as patch 1, taking a few creative liberties with the GHCB spec to justify writing the GHCB GPRs after every VMGEXIT. But, since KVM is effectively writing the GHCB GPRs on every VMRUN, I feel confident in saying that my interpretation of the spec has already been proven correct. The SEV-ES changes are effectively compile tested only, but unless I've overlooked a code path, patch 1 is a nop. Patch 3 definitely needs testing. Paolo, I'd really like to get patches 1 and 2 into 5.11, the code cost of the dirty/available tracking is not trivial. Sean Christopherson (3): KVM: SVM: Unconditionally sync GPRs to GHCB on VMRUN of SEV-ES guest KVM: x86: Revert "KVM: x86: Mark GPRs dirty when written" KVM: SVM: Sync GPRs to the GHCB only after VMGEXIT arch/x86/kvm/kvm_cache_regs.h | 51 +++++++++++++++++------------------ arch/x86/kvm/svm/sev.c | 14 +++++----- arch/x86/kvm/svm/svm.h | 1 + 3 files changed, 34 insertions(+), 32 deletions(-)
Queued 1-2, thanks! Yes, these should be in 5.11. Paolo
