From: Julien Grall <julien.grall.oss@gmail.com>
To: Stefano Stabellini <sstabellini@kernel.org>
Cc: "Wei Liu" <wl@xen.org>,
"Andrew Cooper" <andrew.cooper3@citrix.com>,
"Ian Jackson" <ian.jackson@eu.citrix.com>,
"George Dunlap" <george.dunlap@citrix.com>,
"Bertrand Marquis" <bertrand.marquis@arm.com>,
"Jan Beulich" <jbeulich@suse.com>,
xen-devel <xen-devel@lists.xenproject.org>, nd <nd@arm.com>,
"Volodymyr Babchuk" <Volodymyr_Babchuk@epam.com>,
"Roger Pau Monné" <roger.pau@citrix.com>
Subject: Re: [PATCH 1/2] xen/arm: Convert runstate address during hypcall
Date: Thu, 11 Jun 2020 19:24:35 +0100 [thread overview]
Message-ID: <CAJ=z9a3u7ztgSmJbhjVATrfJEBBVkHbZei6ydBQeV8nzdDFA3Q@mail.gmail.com> (raw)
In-Reply-To: <alpine.DEB.2.21.2006111055360.2815@sstabellini-ThinkPad-T480s>
> > + return -EINVAL;
> > }
> >
> > - __copy_to_guest(runstate_guest(v), &runstate, 1);
> > + v->arch.runstate_guest.page = page;
> > + v->arch.runstate_guest.offset = offset;
> > +
> > + spin_unlock(&v->arch.runstate_guest.lock);
> > +
> > + return 0;
> > +}
> > +
> > +
> > +/* Update per-VCPU guest runstate shared memory area (if registered). */
> > +static void update_runstate_area(struct vcpu *v)
> > +{
> > + struct vcpu_runstate_info *guest_runstate;
> > + void *p;
> > +
> > + spin_lock(&v->arch.runstate_guest.lock);
> >
> > - if ( guest_handle )
> > + if ( v->arch.runstate_guest.page )
> > {
> > - runstate.state_entry_time &= ~XEN_RUNSTATE_UPDATE;
> > + p = __map_domain_page(v->arch.runstate_guest.page);
> > + guest_runstate = p + v->arch.runstate_guest.offset;
> > +
> > + if ( VM_ASSIST(v->domain, runstate_update_flag) )
> > + {
> > + v->runstate.state_entry_time |= XEN_RUNSTATE_UPDATE;
> > + guest_runstate->state_entry_time |= XEN_RUNSTATE_UPDATE;
>
> I think that this write to guest_runstate should use write_atomic or
> another atomic write operation.
I thought about suggesting the same, but guest_copy_* helpers may not
do a single memory write to state_entry_time.
What are you trying to prevent with the write_atomic()?
Cheers,
next prev parent reply other threads:[~2020-06-11 18:25 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-11 11:58 [PATCH 0/2] xen/arm: Convert runstate address during hypcall Bertrand Marquis
2020-06-11 11:58 ` [PATCH 1/2] " Bertrand Marquis
2020-06-11 18:16 ` Stefano Stabellini
2020-06-11 18:24 ` Julien Grall [this message]
2020-06-11 18:50 ` Stefano Stabellini
2020-06-11 19:38 ` Julien Grall
2020-06-12 1:09 ` Stefano Stabellini
2020-06-12 8:13 ` Bertrand Marquis
2020-06-13 0:24 ` Stefano Stabellini
2020-06-15 14:09 ` Bertrand Marquis
2020-06-15 20:30 ` Stefano Stabellini
2020-06-15 20:44 ` Julien Grall
2020-06-12 9:53 ` Julien Grall
2020-06-13 0:24 ` Stefano Stabellini
2020-06-12 8:07 ` Bertrand Marquis
2020-06-12 10:53 ` Julien Grall
2020-06-12 14:13 ` Bertrand Marquis
2020-06-12 19:56 ` Julien Grall
2020-06-12 16:51 ` Bertrand Marquis
2020-06-12 20:31 ` Julien Grall
2020-06-15 14:01 ` Bertrand Marquis
2020-06-11 11:58 ` [PATCH 2/2] xen/arm: Support runstate crossing pages Bertrand Marquis
2020-06-12 1:10 ` Stefano Stabellini
2020-06-12 11:37 ` Julien Grall
2020-06-12 12:14 ` Julien Grall
2020-06-12 16:13 ` Bertrand Marquis
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