[Xen-changelog] [xen stable-4.4] x86: don't change affinity with interrupt unmasked

[patchbot@xxxxxxx]

commit 718f183bf43ffd8d0bea7179d7aa28d9671d18a4
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Tue May 19 11:54:12 2015 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue May 19 11:54:12 2015 +0200

    x86: don't change affinity with interrupt unmasked
    
    With ->startup unmasking the IRQ, setting the affinity afterwards
    without masking the IRQ again is invalid namely for MSI (address and
    data can't be updated atomically and may - at least for MSI-X - be
    cached while unmasked).
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    
    AMD IOMMU: only translate remapped IO-APIC RTEs
    
    1aeb1156fa ("x86 don't change affinity with interrupt unmasked")
    introducing RTE reads prior to the respective interrupt having got
    enabled for the first time uncovered a bug in 2ca9fbd739 ("AMD IOMMU:
    allocate IRTE entries instead of using a static mapping"): We obviously
    shouldn't be translating RTEs for which remapping didn't get set up
    yet.
    
    Reported-by: Sander Eikelenboom <linux@xxxxxxxxxxxxxx>
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Acked-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@xxxxxxx>
    
    master commit: 1aeb1156fa43fe2cd2b5003995b20466cd19a622
    master date: 2015-03-26 11:18:28 +0100
    master commit: c33c51b81c82a51515bf4fa2a9717098c03e5013
    master date: 2015-04-24 12:06:26 +0200
---
 xen/arch/x86/irq.c                       |    5 +++--
 xen/drivers/passthrough/amd/iommu_intr.c |    6 ++++--
 2 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/xen/arch/x86/irq.c b/xen/arch/x86/irq.c
index fd5e7a7..194d508 100644
--- a/xen/arch/x86/irq.c
+++ b/xen/arch/x86/irq.c
@@ -1605,12 +1605,13 @@ int pirq_guest_bind(struct vcpu *v, struct pirq *pirq, 
int will_share)
         init_timer(&action->eoi_timer, irq_guest_eoi_timer_fn, desc, 0);
 
         desc->status |= IRQ_GUEST;
-        desc->status &= ~IRQ_DISABLED;
-        desc->handler->startup(desc);
 
         /* Attempt to bind the interrupt target to the correct CPU. */
         if ( !opt_noirqbalance && (desc->handler->set_affinity != NULL) )
             desc->handler->set_affinity(desc, cpumask_of(v->processor));
+
+        desc->status &= ~IRQ_DISABLED;
+        desc->handler->startup(desc);
     }
     else if ( !will_share || !action->shareable )
     {
diff --git a/xen/drivers/passthrough/amd/iommu_intr.c 
b/xen/drivers/passthrough/amd/iommu_intr.c
index c1b76fb..18d8b5f 100644
--- a/xen/drivers/passthrough/amd/iommu_intr.c
+++ b/xen/drivers/passthrough/amd/iommu_intr.c
@@ -365,15 +365,17 @@ unsigned int amd_iommu_read_ioapic_from_ire(
     unsigned int apic, unsigned int reg)
 {
     unsigned int val = __io_apic_read(apic, reg);
+    unsigned int pin = (reg - 0x10) / 2;
+    unsigned int offset = ioapic_sbdf[IO_APIC_ID(apic)].pin_2_idx[pin];
 
-    if ( !(reg & 1) )
+    if ( !(reg & 1) && offset < INTREMAP_ENTRIES )
     {
-        unsigned int offset = val & (INTREMAP_ENTRIES - 1);
         u16 bdf = ioapic_sbdf[IO_APIC_ID(apic)].bdf;
         u16 seg = ioapic_sbdf[IO_APIC_ID(apic)].seg;
         u16 req_id = get_intremap_requestor_id(seg, bdf);
         const u32 *entry = get_intremap_entry(seg, req_id, offset);
 
+        ASSERT(offset == (val & (INTREMAP_ENTRIES - 1)));
         val &= ~(INTREMAP_ENTRIES - 1);
         val |= get_field_from_reg_u32(*entry,
                                       INT_REMAP_ENTRY_INTTYPE_MASK,
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.4

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