[PATCH 2/3] KVM: nVMX: Fix fail to get nested ack intr's vector during nested vmexit

From: Wanpeng Li
Date: Thu Jul 17 2014 - 00:57:40 EST


WARNING: CPU: 9 PID: 7251 at arch/x86/kvm/vmx.c:8719 nested_vmx_vmexit+0xa4/0x233 [kvm_intel]()
Modules linked in: tun nfsv3 nfs_acl auth_rpcgss oid_registry nfsv4 dns_resolver nfs fscache lockd
sunrpc pci_stub netconsole kvm_intel kvm bridge stp llc autofs4 8021q ipv6 uinput joydev microcode
pcspkr igb i2c_algo_bit ehci_pci ehci_hcd e1000e ixgbe ptp pps_core hwmon mdio i2c_i801 i2c_core
tpm_tis tpm ipmi_si ipmi_msghandler isci libsas scsi_transport_sas button dm_mirror dm_region_hash
dm_log dm_mod
CPU: 9 PID: 7251 Comm: qemu-system-x86 Tainted: G W 3.16.0-rc1 #2
Hardware name: Intel Corporation S2600CP/S2600CP, BIOS RMLSDP.86I.00.29.D696.1311111329 11/11/2013
000000000000220f ffff880ffd107bf8 ffffffff81493563 000000000000220f
0000000000000000 ffff880ffd107c38 ffffffff8103f0eb ffff880ffd107c48
ffffffffa059709a ffff881ffc9e0040 ffff8800b74b8000 00000000ffffffff
Call Trace:
[<ffffffff81493563>] dump_stack+0x49/0x5e
[<ffffffff8103f0eb>] warn_slowpath_common+0x7c/0x96
[<ffffffffa059709a>] ? nested_vmx_vmexit+0xa4/0x233 [kvm_intel]
[<ffffffff8103f11a>] warn_slowpath_null+0x15/0x17
[<ffffffffa059709a>] nested_vmx_vmexit+0xa4/0x233 [kvm_intel]
[<ffffffffa0594295>] ? nested_vmx_exit_handled+0x6a/0x39e [kvm_intel]
[<ffffffffa0537931>] ? kvm_apic_has_interrupt+0x80/0xd5 [kvm]
[<ffffffffa05972ec>] vmx_check_nested_events+0xc3/0xd3 [kvm_intel]
[<ffffffffa051ebe9>] inject_pending_event+0xd0/0x16e [kvm]
[<ffffffffa051efa0>] vcpu_enter_guest+0x319/0x704 [kvm]

After commit 77b0f5d (KVM: nVMX: Ack and write vector info to intr_info if L1
asks us to), "Acknowledge interrupt on exit" behavior can be emulated. Current
logic will ask for intr vector if it is nested vmexit and VM_EXIT_ACK_INTR_ON_EXIT
is set by L1. However, intr vector for posted intr can't be got by generic read
pending interrupt vector and intack routine, there is a requirement to sync from
pir to irr. This patch fix it by ask the intr vector after sync pir to irr.

Signed-off-by: Wanpeng Li <wanpeng.li@xxxxxxxxxxxxxxx>
---
arch/x86/kvm/lapic.c | 1 +
arch/x86/kvm/vmx.c | 3 +++
2 files changed, 4 insertions(+)

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 0069118..b7d45dc 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1637,6 +1637,7 @@ int kvm_get_apic_interrupt(struct kvm_vcpu *vcpu)
apic_clear_irr(vector, apic);
return vector;
}
+EXPORT_SYMBOL_GPL(kvm_get_apic_interrupt);

void kvm_apic_post_state_restore(struct kvm_vcpu *vcpu,
struct kvm_lapic_state *s)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 4ae5ad8..31f1479 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -8697,6 +8697,9 @@ static void nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32 exit_reason,
if ((exit_reason == EXIT_REASON_EXTERNAL_INTERRUPT)
&& nested_exit_intr_ack_set(vcpu)) {
int irq = kvm_cpu_get_interrupt(vcpu);
+
+ if (irq < 0 && kvm_apic_vid_enabled(vcpu->kvm))
+ irq = kvm_get_apic_interrupt(vcpu);
WARN_ON(irq < 0);
vmcs12->vm_exit_intr_info = irq |
INTR_INFO_VALID_MASK | INTR_TYPE_EXT_INTR;
--
1.9.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/