Re: [PATCH v4] x86/HVM: support emulated UMIP

2023-03-20 Thread Jan Beulich
On 17.03.2023 17:09, Roger Pau Monné wrote: > On Fri, Mar 17, 2023 at 04:01:59PM +0100, Jan Beulich wrote: >> On 17.03.2023 15:29, Roger Pau Monné wrote: >>> On Thu, Apr 15, 2021 at 11:47:42AM +0200, Jan Beulich wrote: There are three noteworthy drawbacks: 1) The intercepts we need to ena

Re: [PATCH v4] x86/HVM: support emulated UMIP

2023-03-20 Thread Jan Beulich
On 17.03.2023 17:30, Andrew Cooper wrote: > On 17/03/2023 2:29 pm, Roger Pau Monné wrote: >> On Thu, Apr 15, 2021 at 11:47:42AM +0200, 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 ce

Re: [PATCH v4] x86/HVM: support emulated UMIP

2023-03-17 Thread Andrew Cooper
On 17/03/2023 2:29 pm, Roger Pau Monné wrote: > On Thu, Apr 15, 2021 at 11:47:42AM +0200, 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 ther

Re: [PATCH v4] x86/HVM: support emulated UMIP

2023-03-17 Thread Roger Pau Monné
On Fri, Mar 17, 2023 at 04:01:59PM +0100, Jan Beulich wrote: > On 17.03.2023 15:29, Roger Pau Monné wrote: > > On Thu, Apr 15, 2021 at 11:47:42AM +0200, Jan Beulich wrote: > >> There are three noteworthy drawbacks: > >> 1) The intercepts we need to enable here are CPL-independent, i.e. we > >>n

Re: [PATCH v4] x86/HVM: support emulated UMIP

2023-03-17 Thread Jan Beulich
On 17.03.2023 15:29, Roger Pau Monné wrote: > On Thu, Apr 15, 2021 at 11:47:42AM +0200, 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'

Re: [PATCH v4] x86/HVM: support emulated UMIP

2023-03-17 Thread Roger Pau Monné
On Thu, Apr 15, 2021 at 11:47:42AM +0200, 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 re

[PATCH v4] x86/HVM: support emulated UMIP

2021-04-15 Thread Jan Beulich
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 pr