[PATCH] lib: sbi_trap: Fix hstatus.SPVP update in sbi_trap_redirect()

[Anup Patel]

> -----Original Message-----
> From: Anup Patel
> Sent: 15 August 2020 22:38
> To: Georg Kotheimer <georg.kotheimer at tu-dresden.de>;
> opensbi at lists.infradead.org
> Subject: RE: [PATCH] lib: sbi_trap: Fix hstatus.SPVP update in
> sbi_trap_redirect()
> 
> 
> 
> > -----Original Message-----
> > From: opensbi <opensbi-bounces at lists.infradead.org> On Behalf Of Georg
> > Kotheimer
> > Sent: 15 August 2020 02:31
> > To: opensbi at lists.infradead.org
> > Cc: Georg Kotheimer <georg.kotheimer at tu-dresden.de>
> > Subject: [PATCH] lib: sbi_trap: Fix hstatus.SPVP update in
> > sbi_trap_redirect()
> >
> > When redirecting from VS/VU-mode to HS-mode, hstatus.SPVP was set to
> > the value of mstatus.SPP, as according to the specification both flags
> > should be set to the same value.
> > However, the assignment of SPVP takes place before SPP itself is
> > updated, which results in SPVP having an outdated value.
> >
> > Signed-off-by: Georg Kotheimer <georg.kotheimer at tu-dresden.de>
> > ---
> >  lib/sbi/sbi_trap.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/lib/sbi/sbi_trap.c b/lib/sbi/sbi_trap.c index
> > 930119d..c2bd061
> > 100644
> > --- a/lib/sbi/sbi_trap.c
> > +++ b/lib/sbi/sbi_trap.c
> > @@ -123,7 +123,7 @@ int sbi_trap_redirect(struct sbi_trap_regs *regs,
> >  		/* Update HSTATUS SPVP and SPV bits */
> >  		hstatus = csr_read(CSR_HSTATUS);
> >  		hstatus &= ~HSTATUS_SPVP;
> > -		hstatus |= (regs->mstatus & MSTATUS_SPP) ?
> > HSTATUS_SPVP : 0;
> > +		hstatus |= (prev_mode == PRV_S) ? HSTATUS_SPVP : 0;
> >  		hstatus &= ~HSTATUS_SPV;
> >  		hstatus |= (prev_virt) ? HSTATUS_SPV : 0;
> >  		csr_write(CSR_HSTATUS, hstatus);
> > --
> > 2.25.1
> >
> >
> > --
> > opensbi mailing list
> > opensbi at lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/opensbi
> 
> Nice catch. Looks good to me.
> 
> Reviewed-by: Anup Patel <anup.patel at wdc.com>

Applied this patch to the riscv/opensbi repo.

Thanks,
Anup