Re: [PATCH v2] x86/pv: Inject #UD for missing SYSCALL callbacks

2020-10-14 Thread Andrew Cooper
On 14/10/2020 17:28, Roger Pau Monné wrote: > On Fri, Oct 09, 2020 at 12:53:01PM +0100, Andrew Cooper wrote: >> Despite appearing to be a deliberate design choice of early PV64, the >> resulting behaviour for unregistered SYSCALL callbacks creates an untenable >> testability problem for Xen. Furth

Re: [PATCH v2] x86/pv: Inject #UD for missing SYSCALL callbacks

2020-10-14 Thread Roger Pau Monné
On Fri, Oct 09, 2020 at 12:53:01PM +0100, Andrew Cooper wrote: > Despite appearing to be a deliberate design choice of early PV64, the > resulting behaviour for unregistered SYSCALL callbacks creates an untenable > testability problem for Xen. Furthermore, the behaviour is undocumented, > bizarre,

Re: [PATCH v2] x86/pv: Inject #UD for missing SYSCALL callbacks

2020-10-14 Thread Andrew Cooper
On 14/10/2020 15:16, Roger Pau Monné wrote: >> This change does constitute a change in the PV ABI, for corner cases of a PV >> guest kernel registering neither callback, or not registering the 32bit >> callback when running on AMD/Hygon hardware. > Is there any place suitable to document this behav

Re: [PATCH v2] x86/pv: Inject #UD for missing SYSCALL callbacks

2020-10-14 Thread Andrew Cooper
On 14/10/2020 15:20, Manuel Bouyer wrote: > On Wed, Oct 14, 2020 at 04:16:20PM +0200, Roger Pau Monné wrote: >> [...] >> Would this result in a regression for NetBSD then? Is it fine to see >> #UD regardless of the platform? It's not clear to me from the text >> above whether this change will cause

Re: [PATCH v2] x86/pv: Inject #UD for missing SYSCALL callbacks

2020-10-14 Thread Manuel Bouyer
On Wed, Oct 14, 2020 at 04:16:20PM +0200, Roger Pau Monné wrote: > [...] > Would this result in a regression for NetBSD then? Is it fine to see > #UD regardless of the platform? It's not clear to me from the text > above whether this change will cause issues with NetBSD. AFAIK this should not caus

Re: [PATCH v2] x86/pv: Inject #UD for missing SYSCALL callbacks

2020-10-14 Thread Roger Pau Monné
On Fri, Oct 09, 2020 at 12:53:01PM +0100, Andrew Cooper wrote: > Despite appearing to be a deliberate design choice of early PV64, the > resulting behaviour for unregistered SYSCALL callbacks creates an untenable > testability problem for Xen. Furthermore, the behaviour is undocumented, > bizarre,

Re: [PATCH v2] x86/pv: Inject #UD for missing SYSCALL callbacks

2020-10-09 Thread Andrew Cooper
On 09/10/2020 13:40, Manuel Bouyer wrote: > On Fri, Oct 09, 2020 at 12:53:01PM +0100, Andrew Cooper wrote: >> Despite appearing to be a deliberate design choice of early PV64, the >> resulting behaviour for unregistered SYSCALL callbacks creates an untenable >> testability problem for Xen. Further

Re: [PATCH v2] x86/pv: Inject #UD for missing SYSCALL callbacks

2020-10-09 Thread Manuel Bouyer
On Fri, Oct 09, 2020 at 12:53:01PM +0100, Andrew Cooper wrote: > Despite appearing to be a deliberate design choice of early PV64, the > resulting behaviour for unregistered SYSCALL callbacks creates an untenable > testability problem for Xen. Furthermore, the behaviour is undocumented, > bizarre,

[PATCH v2] x86/pv: Inject #UD for missing SYSCALL callbacks

2020-10-09 Thread Andrew Cooper
Despite appearing to be a deliberate design choice of early PV64, the resulting behaviour for unregistered SYSCALL callbacks creates an untenable testability problem for Xen. Furthermore, the behaviour is undocumented, bizarre, and inconsistent with related behaviour in Xen, and very liable introd