Re: [Qemu-devel] [PATCH v1 1/1] RISC-V: Workaround for critical mstatus.FS MTTCG bug

2018-03-30 Thread Michael Clark
On Fri, Mar 30, 2018 at 12:11 AM, Alex Bennée wrote: > > Michael Clark writes: > > > On Tue, Mar 27, 2018 at 3:17 PM, Philippe Mathieu-Daudé > > > wrote: > > > >> Cc'ing Alex and Richard. > >> > >> On 03/27/2018 04:54 PM, Michael Clark wrote: > >> > This change is a workaround for a bug where m

Re: [Qemu-devel] [PATCH v1 1/1] RISC-V: Workaround for critical mstatus.FS MTTCG bug

2018-03-30 Thread Alex Bennée
Michael Clark writes: > On Tue, Mar 27, 2018 at 3:17 PM, Philippe Mathieu-Daudé > wrote: > >> Cc'ing Alex and Richard. >> >> On 03/27/2018 04:54 PM, Michael Clark wrote: >> > This change is a workaround for a bug where mstatus.FS >> > is not correctly reporting dirty when MTTCG and SMP are >> >

Re: [Qemu-devel] [PATCH v1 1/1] RISC-V: Workaround for critical mstatus.FS MTTCG bug

2018-03-27 Thread Richard Henderson
On 03/28/2018 08:15 AM, Michael Clark wrote: > On looking at this again, I think we may need to remove > the qemu_tcg_mttcg_enabled conditional and always return dirty if the state is > initial or clean, but not off. Yes. > While testing on uniprocessor worked okay, it's likely because we were lu

Re: [Qemu-devel] [PATCH v1 1/1] RISC-V: Workaround for critical mstatus.FS MTTCG bug

2018-03-27 Thread Michael Clark
On Tue, Mar 27, 2018 at 3:17 PM, Philippe Mathieu-Daudé wrote: > Cc'ing Alex and Richard. > > On 03/27/2018 04:54 PM, Michael Clark wrote: > > This change is a workaround for a bug where mstatus.FS > > is not correctly reporting dirty when MTTCG and SMP are > > enabled which results in the floati

Re: [Qemu-devel] [PATCH v1 1/1] RISC-V: Workaround for critical mstatus.FS MTTCG bug

2018-03-27 Thread Philippe Mathieu-Daudé
Cc'ing Alex and Richard. On 03/27/2018 04:54 PM, Michael Clark wrote: > This change is a workaround for a bug where mstatus.FS > is not correctly reporting dirty when MTTCG and SMP are > enabled which results in the floating point register file > not being saved during context switches. This a cri

[Qemu-devel] [PATCH v1 1/1] RISC-V: Workaround for critical mstatus.FS MTTCG bug

2018-03-27 Thread Michael Clark
This change is a workaround for a bug where mstatus.FS is not correctly reporting dirty when MTTCG and SMP are enabled which results in the floating point register file not being saved during context switches. This a critical bug for RISC-V in QEMU as it results in floating point register file corr