Re: [PATCH 6.3 0/5] KVM CR0.WP series backport

[Sean Christopherson <seanjc@google.com>]

On Fri, May 12, 2023, Mathias Krause wrote:
> This is a backport of the CR0.WP KVM series[1] to Linux v6.3.
> 
> As the original series is based on v6.3-rc1, it's mostly a verbatim
> port. Only the last patch needed adaption, as it was a fix based on
> v6.4-rc1. However, as for the v6.2 backport, I simply changed the code
> to make use of the older kvm_is_cr0_bit_set() helper.
> 
> I used 'ssdd 10 50000' from rt-tests[2] as a micro-benchmark, running on
> a grsecurity L1 VM. Below table shows the results (runtime in seconds,
> lower is better):
> 
>                        legacy     TDP
>     Linux v6.3.1        7.60s    8.29s
>     + patches           3.39s    3.39s
> 
>     Linux v6.3.2        7.82s    7.81s
>     + patches           3.38s    3.38s
> 
> I left out the shadow MMU tests this time, as they're not impacted
> anyways, only take a lot of time to run. I did, however, include
> separate tests for v6.3.{1,2} -- not because I had an outdated
> linux-stable git tree lying around *cough, cough* but because the later
> includes commit 2ec1fe292d6e ("KVM: x86: Preserve TDP MMU roots until
> they are explicitly invalidated"), the commit I wanted to benchmark
> against anyways. Apparently, it has only a minor impact for our use
> case, so this series is still wanted, imho.
> 
> Please consider applying.
> 
> Thanks,
> Mathias
> 
> [1] https://lore.kernel.org/kvm/20230322013731.102955-1-minipli@grsecurity.net/
> [2] https://git.kernel.org/pub/scm/utils/rt-tests/rt-tests.git
> 
> 
> Mathias Krause (3):
>   KVM: x86: Do not unload MMU roots when only toggling CR0.WP with TDP
>     enabled
>   KVM: x86: Make use of kvm_read_cr*_bits() when testing bits
>   KVM: VMX: Make CR0.WP a guest owned bit
> 
> Paolo Bonzini (1):
>   KVM: x86/mmu: Avoid indirect call for get_cr3
> 
> Sean Christopherson (1):
>   KVM: x86/mmu: Refresh CR0.WP prior to checking for emulated permission
>     faults

Acked-by: Sean Christopherson <seanjc@google.com>