From mboxrd@z Thu Jan 1 00:00:00 1970 From: Feng Wu Subject: [PATCH v9 03/17] iommu: Add iommu_intpost to control VT-d Posted-Interrupts feature Date: Tue, 3 Nov 2015 16:43:13 +0800 Message-ID: <1446540207-4806-4-git-send-email-feng.wu@intel.com> References: <1446540207-4806-1-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: <1446540207-4806-1-git-send-email-feng.wu@intel.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: xen-devel@lists.xen.org Cc: Kevin Tian , Feng Wu , Jan Beulich List-Id: xen-devel@lists.xenproject.org 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 variable 'iommu_intpost' to control whether enable VT-d posted-interrupt or not in the generic IOMMU code. CC: Jan Beulich CC: Kevin Tian Signed-off-by: Feng Wu Reviewed-by: Kevin Tian Reviewed-by: Konrad Rzeszutek Wilk Acked-by: Jan Beulich --- v5: - Remove the "if no intremap then no intpost" logic in parse_iommu_param(), which can be covered in iommu_setup() v3: - Remove pointless initializer for 'iommu_intpost'. - Some adjustment for "if no intremap then no intpost" logic. * For parse_iommu_param(), move it to the end of the function, so we don't need to add the some logic when introduing the new kernel parameter 'intpost' in later patch. * Add this logic in iommu_setup() after iommu_hardware_setup() is called. xen/drivers/passthrough/iommu.c | 13 ++++++++++++- xen/include/xen/iommu.h | 2 +- 2 files changed, 13 insertions(+), 2 deletions(-) diff --git a/xen/drivers/passthrough/iommu.c b/xen/drivers/passthrough/iommu.c index fc7831e..36d5cc0 100644 --- a/xen/drivers/passthrough/iommu.c +++ b/xen/drivers/passthrough/iommu.c @@ -51,6 +51,14 @@ bool_t __read_mostly iommu_passthrough; bool_t __read_mostly iommu_snoop = 1; bool_t __read_mostly iommu_qinval = 1; bool_t __read_mostly iommu_intremap = 1; + +/* + * In the current implementation of VT-d posted interrupts, in some extreme + * cases, the per cpu list which saves the blocked vCPU will be very long, + * and this will affect the interrupt latency, so let this feature off by + * default until we find a good solution to resolve it. + */ +bool_t __read_mostly iommu_intpost; bool_t __read_mostly iommu_hap_pt_share = 1; bool_t __read_mostly iommu_debug; bool_t __read_mostly amd_iommu_perdev_intremap = 1; @@ -307,6 +315,9 @@ int __init iommu_setup(void) panic("Couldn't enable %s and iommu=required/force", !iommu_enabled ? "IOMMU" : "Interrupt Remapping"); + if ( !iommu_intremap ) + iommu_intpost = 0; + if ( !iommu_enabled ) { iommu_snoop = 0; @@ -374,7 +385,7 @@ void iommu_crash_shutdown(void) const struct iommu_ops *ops = iommu_get_ops(); if ( iommu_enabled ) ops->crash_shutdown(); - iommu_enabled = iommu_intremap = 0; + iommu_enabled = iommu_intremap = iommu_intpost = 0; } int iommu_get_reserved_device_memory(iommu_grdm_t *func, void *ctxt) diff --git a/xen/include/xen/iommu.h b/xen/include/xen/iommu.h index 8f3a20e..1f5d04a 100644 --- a/xen/include/xen/iommu.h +++ b/xen/include/xen/iommu.h @@ -30,7 +30,7 @@ extern bool_t iommu_enable, iommu_enabled; extern bool_t force_iommu, iommu_verbose; extern bool_t iommu_workaround_bios_bug, iommu_igfx, iommu_passthrough; -extern bool_t iommu_snoop, iommu_qinval, iommu_intremap; +extern bool_t iommu_snoop, iommu_qinval, iommu_intremap, iommu_intpost; extern bool_t iommu_hap_pt_share; extern bool_t iommu_debug; extern bool_t amd_iommu_perdev_intremap; -- 2.1.0