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authorMarc Zyngier <marc.zyngier@arm.com>2018-03-06 21:48:01 +0000
committerMarc Zyngier <marc.zyngier@arm.com>2018-03-14 18:31:04 +0000
commit16ca6a607d84bef0129698d8d808f501afd08d43 (patch)
treedd8c4a36c3c185e82003cd125a092cb42845de21 /include/linux/irqchip
parent76600428c3677659e3c3633bb4f2ea302220a275 (diff)
KVM: arm/arm64: vgic: Don't populate multiple LRs with the same vintid
The vgic code is trying to be clever when injecting GICv2 SGIs, and will happily populate LRs with the same interrupt number if they come from multiple vcpus (after all, they are distinct interrupt sources). Unfortunately, this is against the letter of the architecture, and the GICv2 architecture spec says "Each valid interrupt stored in the List registers must have a unique VirtualID for that virtual CPU interface.". GICv3 has similar (although slightly ambiguous) restrictions. This results in guests locking up when using GICv2-on-GICv3, for example. The obvious fix is to stop trying so hard, and inject a single vcpu per SGI per guest entry. After all, pending SGIs with multiple source vcpus are pretty rare, and are mostly seen in scenario where the physical CPUs are severely overcomitted. But as we now only inject a single instance of a multi-source SGI per vcpu entry, we may delay those interrupts for longer than strictly necessary, and run the risk of injecting lower priority interrupts in the meantime. In order to address this, we adopt a three stage strategy: - If we encounter a multi-source SGI in the AP list while computing its depth, we force the list to be sorted - When populating the LRs, we prevent the injection of any interrupt of lower priority than that of the first multi-source SGI we've injected. - Finally, the injection of a multi-source SGI triggers the request of a maintenance interrupt when there will be no pending interrupt in the LRs (HCR_NPIE). At the point where the last pending interrupt in the LRs switches from Pending to Active, the maintenance interrupt will be delivered, allowing us to add the remaining SGIs using the same process. Cc: stable@vger.kernel.org Fixes: 0919e84c0fc1 ("KVM: arm/arm64: vgic-new: Add IRQ sync/flush framework") Acked-by: Christoffer Dall <cdall@kernel.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Diffstat (limited to 'include/linux/irqchip')
-rw-r--r--include/linux/irqchip/arm-gic-v3.h1
-rw-r--r--include/linux/irqchip/arm-gic.h1
2 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/irqchip/arm-gic-v3.h b/include/linux/irqchip/arm-gic-v3.h
index c00c4c33e432..b26eccc78fb1 100644
--- a/include/linux/irqchip/arm-gic-v3.h
+++ b/include/linux/irqchip/arm-gic-v3.h
@@ -503,6 +503,7 @@
#define ICH_HCR_EN (1 << 0)
#define ICH_HCR_UIE (1 << 1)
+#define ICH_HCR_NPIE (1 << 3)
#define ICH_HCR_TC (1 << 10)
#define ICH_HCR_TALL0 (1 << 11)
#define ICH_HCR_TALL1 (1 << 12)
diff --git a/include/linux/irqchip/arm-gic.h b/include/linux/irqchip/arm-gic.h
index d3453ee072fc..68d8b1f73682 100644
--- a/include/linux/irqchip/arm-gic.h
+++ b/include/linux/irqchip/arm-gic.h
@@ -84,6 +84,7 @@
#define GICH_HCR_EN (1 << 0)
#define GICH_HCR_UIE (1 << 1)
+#define GICH_HCR_NPIE (1 << 3)
#define GICH_LR_VIRTUALID (0x3ff << 0)
#define GICH_LR_PHYSID_CPUID_SHIFT (10)