Re: [PATCH] x86/HVM: support emulated UMIP

[Jan Beulich <jbeulich@xxxxxxxx>]

On 29.01.2021 12:45, Jan Beulich wrote:
> There are three noteworthy drawbacks:
> 1) The intercepts we need to enable here are CPL-independent, i.e. we
>    now have to emulate certain instructions for ring 0.
> 2) On VMX there's no intercept for SMSW, so the emulation isn't really
>    complete there.
> 3) The CR4 write intercept on SVM is lower priority than all exception
>    checks, so we need to intercept #GP.
> Therefore this emulation doesn't get offered to guests by default.
> 
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
> ---
> v3: Don't offer emulation by default. Re-base.
> v2: Split off the x86 insn emulator part. Re-base. Use hvm_featureset
>     in hvm_cr4_guest_reserved_bits().

As per this, the title was meant to start [PATCH v3]; sorry.
The v2 submission was quite some time ago, though.

Jan