Re: [PATCH] x86emul: correct put_fpu()'s segment selector handling

2025-01-07 Thread Andrew Cooper
On 07/01/2025 3:41 pm, Jan Beulich wrote: > On 07.01.2025 16:37, Andrew Cooper wrote: >> On 07/01/2025 2:33 pm, Jan Beulich wrote: >>> All selector fields under ctxt->regs are (normally) poisoned in the HVM >>> case, and the four ones besides CS and SS are potentially stale for PV. >>> Avoid using

Re: [PATCH] x86emul: correct put_fpu()'s segment selector handling

2025-01-07 Thread Jan Beulich
On 07.01.2025 16:37, Andrew Cooper wrote: > On 07/01/2025 2:33 pm, Jan Beulich wrote: >> All selector fields under ctxt->regs are (normally) poisoned in the HVM >> case, and the four ones besides CS and SS are potentially stale for PV. >> Avoid using them in the hypervisor incarnation of the emulat

Re: [PATCH] x86emul: correct put_fpu()'s segment selector handling

2025-01-07 Thread Andrew Cooper
On 07/01/2025 2:33 pm, Jan Beulich wrote: > All selector fields under ctxt->regs are (normally) poisoned in the HVM > case, and the four ones besides CS and SS are potentially stale for PV. > Avoid using them in the hypervisor incarnation of the emulator, when > trying to cover for a missing ->read

[PATCH] x86emul: correct put_fpu()'s segment selector handling

2025-01-07 Thread Jan Beulich
All selector fields under ctxt->regs are (normally) poisoned in the HVM case, and the four ones besides CS and SS are potentially stale for PV. Avoid using them in the hypervisor incarnation of the emulator, when trying to cover for a missing ->read_segment() hook. To make sure there's always a va