From: "Jan Beulich" <JBeulich@suse.com> To: Paul Durrant <email@example.com> Cc: Andrew Cooper <firstname.lastname@example.org>, Keir Fraser <email@example.com>, firstname.lastname@example.org Subject: Re: [PATCH v2] x86/hvm/viridian: fix the TLB flush hypercall Date: Thu, 17 Mar 2016 02:35:17 -0600 [thread overview] Message-ID: <56EA7A5502000078000DD9EF@prv-mh.provo.novell.com> (raw) In-Reply-To: <email@example.com> >>> 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> _______________________________________________ Xen-devel mailing list Xenemail@example.com http://lists.xen.org/xen-devel
next prev parent reply other threads:[~2016-03-17 8:35 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 [this message] 2016-03-17 10:30 ` Andrew Cooper
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