From: Andrew Cooper <email@example.com> To: Jan Beulich <JBeulich@suse.com>, Paul Durrant <firstname.lastname@example.org> Cc: email@example.com, Keir Fraser <firstname.lastname@example.org> Subject: Re: [PATCH v2] x86/hvm/viridian: fix the TLB flush hypercall Date: Thu, 17 Mar 2016 10:30:10 +0000 [thread overview] Message-ID: <56EA8732.email@example.com> (raw) In-Reply-To: <56EA7A5502000078000DD9EF@prv-mh.provo.novell.com> On 17/03/16 08:35, Jan Beulich wrote: >>>> On 16.03.16 at 15:21, <firstname.lastname@example.org> wrote: >> Commit b38d426a "flush remote tlbs by hypercall" add support to allow >> Windows to request flush of remote TLB via hypercall rather than IPI. >> Unfortunately it seems that this code was broken in a couple of ways: >> >> 1) The allocation of the per-vcpu ipi mask is gated on whether the >> domain has viridian features enabled but the call to allocate is >> made before the toolstack has enabled those features. This results >> in a NULL pointer dereference. >> >> 2) One of the flush hypercall variants is a rep op, but the code >> does not update the output data with the reps completed. Hence the >> guest will spin repeatedly making the hypercall because it believes >> it has uncompleted reps. >> >> This patch fixes both of these issues as follows: >> >> 1) The ipi mask need only be per-pcpu so it is made a per-pcpu static >> to avoid the need for allocation. >> >> 2) The rep complete count is updated to the rep count since the single >> flush that Xen does covers all reps anyway. >> >> Signed-off-by: Paul Durrant <email@example.com> > Reviewed-by: Jan Beulich <firstname.lastname@example.org> > Reviewed-by: Andrew Cooper <email@example.com> _______________________________________________ Xen-devel mailing list Xenfirstname.lastname@example.org http://lists.xen.org/xen-devel
prev parent reply other threads:[~2016-03-17 10:30 UTC|newest] Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-03-16 14:21 Paul Durrant 2016-03-16 15:35 ` Jan Beulich 2016-03-16 17:35 ` Paul Durrant 2016-03-17 8:11 ` Jan Beulich 2016-03-17 8:14 ` Paul Durrant 2016-03-17 8:35 ` Jan Beulich 2016-03-17 10:30 ` Andrew Cooper [this message]
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