From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Tian, Kevin" Subject: Re: [v3 05/15] vt-d: VT-d Posted-Interrupts feature detection Date: Wed, 8 Jul 2015 07:32:13 +0000 Message-ID: References: <1435123109-10481-1-git-send-email-feng.wu@intel.com> <1435123109-10481-6-git-send-email-feng.wu@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1435123109-10481-6-git-send-email-feng.wu@intel.com> Content-Language: en-US List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: "Wu, Feng" , "xen-devel@lists.xen.org" Cc: "Zhang, Yang Z" , "andrew.cooper3@citrix.com" , "keir@xen.org" , "george.dunlap@eu.citrix.com" , "jbeulich@suse.com" List-Id: xen-devel@lists.xenproject.org > From: Wu, Feng > Sent: Wednesday, June 24, 2015 1:18 PM > > VT-d Posted-Interrupts is an enhancement to CPU side Posted-Interrupt. > With VT-d Posted-Interrupts enabled, external interrupts from > direct-assigned devices can be delivered to guests without VMM > intervention when guest is running in non-root mode. > > This patch adds feature detection logic for VT-d posted-interrupt. > > Signed-off-by: Feng Wu > --- > v3: > - Remove the "if no intremap then no intpost" logic in > intel_vtd_setup(), it is covered in the iommu_setup(). > - Add "if no intremap then no intpost" logic in the end > of init_vtd_hw() which is called by vtd_resume(). > > So the logic exists in the following three places: > - parse_iommu_param() > - iommu_setup() > - init_vtd_hw() > > xen/drivers/passthrough/vtd/iommu.c | 18 ++++++++++++++++-- > xen/drivers/passthrough/vtd/iommu.h | 1 + > 2 files changed, 17 insertions(+), 2 deletions(-) > > diff --git a/xen/drivers/passthrough/vtd/iommu.c > b/xen/drivers/passthrough/vtd/iommu.c > index 9053a1f..4221185 100644 > --- a/xen/drivers/passthrough/vtd/iommu.c > +++ b/xen/drivers/passthrough/vtd/iommu.c > @@ -2071,6 +2071,9 @@ static int init_vtd_hw(void) > disable_intremap(drhd->iommu); > } > > + if ( !iommu_intremap ) > + iommu_intpost = 0; > + > /* > * Set root entries for each VT-d engine. After set root entry, > * must globally invalidate context cache, and then globally > @@ -2133,8 +2136,8 @@ int __init intel_vtd_setup(void) > } > > /* We enable the following features only if they are supported by all VT-d > - * engines: Snoop Control, DMA passthrough, Queued Invalidation and > - * Interrupt Remapping. > + * engines: Snoop Control, DMA passthrough, Queued Invalidation, Interrupt > + * Remapping, and Posted Interrupt > */ > for_each_drhd_unit ( drhd ) > { > @@ -2162,6 +2165,15 @@ int __init intel_vtd_setup(void) > if ( iommu_intremap && !ecap_intr_remap(iommu->ecap) ) > iommu_intremap = 0; > > + /* > + * We cannot use posted interrupt if X86_FEATURE_CX16 is > + * not supported, since we count on this feature to > + * atomically update 16-byte IRTE in posted format. > + */ > + if ( !iommu_intremap && > + (!cap_intr_post(iommu->cap) || !cpu_has_cx16) ) > + iommu_intpost = 0; > + Looks a typo here. &&->|| Thanks Kevin