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Commit de81c2f9 authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
Browse files

KVM: x86: WARN_ONCE if sending a PV IPI returns a fatal error 



KVM hypercalls return a negative value error code in case of a fatal
error, e.g. when the hypercall isn't supported or was made with invalid
parameters.  WARN_ONCE on fatal errors when sending PV IPIs as any such
error all but guarantees an SMP system will hang due to a missing IPI.

Fixes: aaffcfd1 ("KVM: X86: Implement PV IPIs in linux guest")
Cc: stable@vger.kernel.org
Cc: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: default avatarSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 1ed199a4

arch/x86/kernel/kvm.c

+5 −2
Original line number Diff line number Diff line
@@ -457,6 +457,7 @@ static void __send_ipi_mask(const struct cpumask *mask, int vector) 
#else

	u64 ipi_bitmap = 0;

#endif

	long ret;



	if (cpumask_empty(mask))

		return;
@@ -482,8 +483,9 @@ static void __send_ipi_mask(const struct cpumask *mask, int vector) 
		} else if (apic_id < min + KVM_IPI_CLUSTER_SIZE) {

			max = apic_id < max ? max : apic_id;

		} else {

			kvm_hypercall4(KVM_HC_SEND_IPI, (unsigned long)ipi_bitmap,

			ret = kvm_hypercall4(KVM_HC_SEND_IPI, (unsigned long)ipi_bitmap,

				(unsigned long)(ipi_bitmap >> BITS_PER_LONG), min, icr);

			WARN_ONCE(ret < 0, "KVM: failed to send PV IPI: %ld", ret);

			min = max = apic_id;

			ipi_bitmap = 0;

		}
@@ -491,8 +493,9 @@ static void __send_ipi_mask(const struct cpumask *mask, int vector) 
	}



	if (ipi_bitmap) {

		kvm_hypercall4(KVM_HC_SEND_IPI, (unsigned long)ipi_bitmap,

		ret = kvm_hypercall4(KVM_HC_SEND_IPI, (unsigned long)ipi_bitmap,

			(unsigned long)(ipi_bitmap >> BITS_PER_LONG), min, icr);

		WARN_ONCE(ret < 0, "KVM: failed to send PV IPI: %ld", ret);

	}



	local_irq_restore(flags);