From: Jan Beulich <jbeulich@suse.com>
To: "xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>
Cc: Kevin Tian <kevin.tian@intel.com>, Paul Durrant <paul@xen.org>,
Ian Jackson <ian.jackson@citrix.com>
Subject: [PATCH 3/3][4.16?] VT-d: don't needlessly engage the untrusted-MSI workaround
Date: Tue, 9 Nov 2021 15:58:17 +0100 [thread overview]
Message-ID: <466baa9f-38bc-99b8-6403-24e9384820b3@suse.com> (raw)
In-Reply-To: <d8295304-d81d-1d11-9bc2-d2539bf5a96a@suse.com>
The quarantine domain doesn't count as a DomU, as it won't itself
trigger any bad behavior. The workaround only needs enabling when an
actual DomU is about to gain control of a device. This then also means
enabling of the workaround can be deferred until immediately ahead of
the call to domain_context_mapping(). While there also stop open-coding
is_hardware_domain().
Fixes: 319f9a0ba94c ("passthrough: quarantine PCI devices")
Signed-off-by: Jan Beulich <jbeulich@suse.com>
--- a/xen/drivers/passthrough/vtd/iommu.c
+++ b/xen/drivers/passthrough/vtd/iommu.c
@@ -2404,14 +2404,6 @@ static int reassign_device_ownership(
int ret;
/*
- * Devices assigned to untrusted domains (here assumed to be any domU)
- * can attempt to send arbitrary LAPIC/MSI messages. We are unprotected
- * by the root complex unless interrupt remapping is enabled.
- */
- if ( (target != hardware_domain) && !iommu_intremap )
- untrusted_msi = true;
-
- /*
* If the device belongs to the hardware domain, and it has RMRR, don't
* remove it from the hardware domain, because BIOS may use RMRR at
* booting time.
@@ -2455,6 +2447,15 @@ static int reassign_device_ownership(
if ( !has_arch_pdevs(target) )
vmx_pi_hooks_assign(target);
+ /*
+ * Devices assigned to untrusted domains (here assumed to be any domU)
+ * can attempt to send arbitrary LAPIC/MSI messages. We are unprotected
+ * by the root complex unless interrupt remapping is enabled.
+ */
+ if ( !iommu_intremap && !is_hardware_domain(target) &&
+ !is_system_domain(target) )
+ untrusted_msi = true;
+
ret = domain_context_mapping(target, devfn, pdev);
if ( ret )
{
next prev parent reply other threads:[~2021-11-09 14:58 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-09 14:55 [PATCH 0/3][4.16?] VT-d: misc (regression) fixes Jan Beulich
2021-11-09 14:57 ` [PATCH 1/3][4.16?] VT-d: per-domain IOMMU bitmap needs to have dynamic size Jan Beulich
2021-11-09 14:57 ` [PATCH 2/3][4.16?] VT-d: fix reduced page table levels support when sharing tables Jan Beulich
2021-11-09 14:58 ` Jan Beulich [this message]
2021-11-10 6:46 ` [PATCH 0/3][4.16?] VT-d: misc (regression) fixes Tian, Kevin
2021-11-11 9:32 ` Jan Beulich
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