From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:37507) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1g9PVL-0007Xr-Ee for qemu-devel@nongnu.org; Mon, 08 Oct 2018 02:59:04 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1g9PKe-0004J7-0t for qemu-devel@nongnu.org; Mon, 08 Oct 2018 02:48:01 -0400 Received: from mx1.redhat.com ([209.132.183.28]:41190) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1g9PKd-0004Eq-Qg for qemu-devel@nongnu.org; Mon, 08 Oct 2018 02:47:55 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 32DBE30820F0 for ; Mon, 8 Oct 2018 06:47:55 +0000 (UTC) From: Peter Xu Date: Mon, 8 Oct 2018 14:47:13 +0800 Message-Id: <20181008064713.27349-3-peterx@redhat.com> In-Reply-To: <20181008064713.27349-1-peterx@redhat.com> References: <20181008064713.27349-1-peterx@redhat.com> Subject: [Qemu-devel] [PATCH v2 2/2] intel_iommu: handle invalid ce for shadow sync List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Maxime Coquelin , Eric Auger , peterx@redhat.com, Jason Wang , "Michael S . Tsirkin" , Alex Williamson , Pei Zhang We should handle VTD_FR_CONTEXT_ENTRY_P properly when synchronizing shadow page tables. Having invalid context entry there is perfectly valid when we move a device out of an existing domain. When that happens, instead of posting an error we invalidate the whole region. Without this patch, QEMU will crash if we do these steps: (1) start QEMU with VT-d IOMMU and two 10G NICs (ixgbe) (2) bind the NICs with vfio-pci in the guest (3) start testpmd with the NICs applied (4) stop testpmd (5) rebind the NIC back to ixgbe kernel driver The patch should fix it. Reported-by: Pei Zhang Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1627272 Signed-off-by: Peter Xu --- hw/i386/intel_iommu.c | 20 +++++++++++++++++++- 1 file changed, 19 insertions(+), 1 deletion(-) diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c index d6b4f8705d..b0884e87e8 100644 --- a/hw/i386/intel_iommu.c +++ b/hw/i386/intel_iommu.c @@ -37,6 +37,8 @@ #include "kvm_i386.h" #include "trace.h" +static void vtd_address_space_unmap(VTDAddressSpace *as, IOMMUNotifier *n); + static void vtd_define_quad(IntelIOMMUState *s, hwaddr addr, uint64_t val, uint64_t wmask, uint64_t w1cmask) { @@ -1056,12 +1058,28 @@ static int vtd_sync_shadow_page_table(VTDAddressSpace *vtd_as) { int ret; VTDContextEntry ce; + IOMMUNotifier *n; ret = vtd_dev_to_context_entry(vtd_as->iommu_state, pci_bus_num(vtd_as->bus), vtd_as->devfn, &ce); if (ret) { - return ret; + if (ret == -VTD_FR_CONTEXT_ENTRY_P) { + /* + * It's a valid scenario to have a context entry that is + * not present. For example, when a device is removed + * from an existing domain then the context entry will be + * zeroed by the guest before it was put into another + * domain. When this happens, instead of synchronizing + * the shadow pages we should invalidate all existing + * mappings and notify the backends. + */ + IOMMU_NOTIFIER_FOREACH(n, &vtd_as->iommu) { + vtd_address_space_unmap(vtd_as, n); + } + } else { + return ret; + } } return vtd_sync_shadow_page_table_range(vtd_as, &ce, 0, UINT64_MAX); -- 2.17.1