vtd: make sure QI/IR are disabled before initialisation

BIOS might pass control to Xen leaving QI and/or IR in enabled and/or
partially configured state. In case of x2APIC code path where EIM is
enabled early in boot - those are correctly disabled by Xen before any
attempt to configure. But for xAPIC that step is missing which was
proven to cause QI initialization failures on some ICX based platforms
where QI is left pre-enabled and partially configured by BIOS. That
problem becomes hard to avoid since those platforms are shipped with
x2APIC opt out being advertised by default at the same time by firmware.

Unify the behaviour between x2APIC and xAPIC code paths keeping that in
line with what Linux does.

Signed-off-by: Igor Druzhinin <igor.druzhinin@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Release-Acked-by: Ian Jackson <iwj@xenproject.org>

diff --git a/xen/arch/x86/apic.c b/xen/arch/x86/apic.c
index 7497ddb5dae7ce9d9f3cd175c130251ad316ee7c..8ab82145593a38741df0377c86fd33282745a528 100644 (file)
--- a/xen/arch/x86/apic.c
+++ b/xen/arch/x86/apic.c
@@ -47,7 +47,7 @@ static bool __read_mostly tdt_enabled;
 static bool __initdata tdt_enable = true;
 boolean_param("tdt", tdt_enable);
 
-static bool __read_mostly iommu_x2apic_enabled;
+bool __read_mostly iommu_x2apic_enabled;
 
 static struct {
     int active;

diff --git a/xen/drivers/passthrough/vtd/iommu.c b/xen/drivers/passthrough/vtd/iommu.c
index 475efb3be3bdbcf395b3260e3717c1236a3c1459..9b58d566c8227756bff7294d99de2bfe2088ae3a 100644 (file)
--- a/xen/drivers/passthrough/vtd/iommu.c
+++ b/xen/drivers/passthrough/vtd/iommu.c
@@ -2101,7 +2101,7 @@ static int __must_check init_vtd_hw(void)
     u32 sts;
 
     /*
-     * Basic VT-d HW init: set VT-d interrupt, clear VT-d faults.  
+     * Basic VT-d HW init: set VT-d interrupt, clear VT-d faults, etc.
      */
     for_each_drhd_unit ( drhd )
     {
@@ -2111,6 +2111,16 @@ static int __must_check init_vtd_hw(void)
 
         clear_fault_bits(iommu);
 
+        /*
+         * Disable interrupt remapping and queued invalidation if
+         * already enabled by BIOS in case we've not initialized it yet.
+         */
+        if ( !iommu_x2apic_enabled )
+        {
+            disable_intremap(iommu);
+            disable_qinval(iommu);
+        }
+
         spin_lock_irqsave(&iommu->register_lock, flags);
         sts = dmar_readl(iommu->reg, DMAR_FECTL_REG);
         sts &= ~DMA_FECTL_IM;

diff --git a/xen/include/asm-x86/apic.h b/xen/include/asm-x86/apic.h
index 8ddb896ee9d33eb94635b6bf0e9f879f1b6c7640..2fe54bbf1c516507314c0d2e3af299afe11e5685 100644 (file)
--- a/xen/include/asm-x86/apic.h
+++ b/xen/include/asm-x86/apic.h
@@ -24,6 +24,7 @@ enum apic_mode {
     APIC_MODE_X2APIC    /* x2APIC mode - common for large MP machines */
 };
 
+extern bool iommu_x2apic_enabled;
 extern u8 apic_verbosity;
 extern bool directed_eoi_enabled;