fastpath_t? __no_kcsan? Both?
From: Paul E. McKenney
Date: Mon Jun 15 2020 - 00:20:31 EST
Hello!
I get the following conflict when rebasing 39a8c47635b0 ("kvm/svm:
Disable KCSAN for svm_vcpu_run()") onto v5.8-rc1:
<<<<<<< 6c410247efb2d3907b508a2448ab9ab1c86d938c
static fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu)
=======
static __no_kcsan void svm_vcpu_run(struct kvm_vcpu *vcpu)
>>>>>>> kvm/svm: Disable KCSAN for svm_vcpu_run()
The "natural" resolution would be this:
static fastpath_t __no_kcsan void svm_vcpu_run(struct kvm_vcpu *vcpu)
But does that make sense?
I have dropped this commit for the time being. Please either
let me know the proper resolution or submit a fresh patch,
your choice.
Thanx, Paul
------------------------------------------------------------------------
commit 39a8c47635b00ebf9a3c52d9ca357fff5a8b36e3
Author: Qian Cai <cai@xxxxxx>
Date: Wed Apr 15 11:37:09 2020 -0400
kvm/svm: Disable KCSAN for svm_vcpu_run()
For some reasons, running a simple qemu-kvm command with KCSAN will
reset AMD hosts. It turns out svm_vcpu_run() could not be instrumented.
This commit therefore disables it for now.
# /usr/libexec/qemu-kvm -name ubuntu-18.04-server-cloudimg -cpu host
-smp 2 -m 2G -hda ubuntu-18.04-server-cloudimg.qcow2
=== console output ===
Kernel 5.6.0-next-20200408+ on an x86_64
hp-dl385g10-05 login:
<...host reset...>
HPE ProLiant System BIOS A40 v1.20 (03/09/2018)
(C) Copyright 1982-2018 Hewlett Packard Enterprise Development LP
Early system initialization, please wait...
Acked-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Qian Cai <cai@xxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 38f6aee..c6f89e4 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -3280,7 +3280,7 @@ static void svm_cancel_injection(struct kvm_vcpu *vcpu)
void __svm_vcpu_run(unsigned long vmcb_pa, unsigned long *regs);
-static void svm_vcpu_run(struct kvm_vcpu *vcpu)
+static __no_kcsan void svm_vcpu_run(struct kvm_vcpu *vcpu)
{
struct vcpu_svm *svm = to_svm(vcpu);