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From:   Wanpeng Li <kernellwp@gmail.com>
To:     linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc:     Paolo Bonzini <pbonzini@redhat.com>,
        =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= <rkrcmar@redhat.com>,
        Tonny Lu <tonnylu@tencent.com>
Subject: [PATCH] KVM: X86: Extend MAX_IRQ_ROUTES to 4096
Date:   Thu, 19 Apr 2018 05:30:40 -0700
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From: Wanpeng Li <wanpengli@tencent.com>

Our virtual machines make use of device assignment by configuring
12 NVMe disks for high I/O performance. Each NVMe device has 129 
MSI-X Table entries:
Capabilities: [50] MSI-X: Enable+ Count=129 Masked-Vector table: BAR=0 offset=00002000
The windows virtual machines fail to boot since they will map the number of 
MSI-table entries that the NVMe hardware reported to the bus to msi routing 
table, this will exceed the 1024. This patch extends MAX_IRQ_ROUTES to 4096,
In the future this might be extended if needed.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Tonny Lu <tonnylu@tencent.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Tonny Lu <tonnylu@tencent.com>
---
 include/linux/kvm_host.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 6930c63..815ae66 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1050,7 +1050,7 @@ static inline int mmu_notifier_retry(struct kvm *kvm, unsigned long mmu_seq)
 #elif defined(CONFIG_ARM64)
 #define KVM_MAX_IRQ_ROUTES 4096
 #else
-#define KVM_MAX_IRQ_ROUTES 1024
+#define KVM_MAX_IRQ_ROUTES 4096
 #endif
 
 bool kvm_arch_can_set_irq_routing(struct kvm *kvm);
-- 
2.7.4