linux-kernel - [RFC PATCH 1/3] KVM: Export kvm_make_all_cpus_request() for use in marking VMs as bugged

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Date:   Wed, 23 Sep 2020 15:45:28 -0700
From:   Sean Christopherson <sean.j.christopherson@...el.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Sean Christopherson <sean.j.christopherson@...el.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, Marc Zyngier <maz@...nel.org>,
        James Morse <james.morse@....com>,
        Julien Thierry <julien.thierry.kdev@...il.com>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        linux-arm-kernel@...ts.infradead.org,
        Huacai Chen <chenhc@...ote.com>,
        Aleksandar Markovic <aleksandar.qemu.devel@...il.com>,
        linux-mips@...r.kernel.org, Paul Mackerras <paulus@...abs.org>,
        kvm-ppc@...r.kernel.org,
        Christian Borntraeger <borntraeger@...ibm.com>,
        Janosch Frank <frankja@...ux.ibm.com>,
        David Hildenbrand <david@...hat.com>,
        Cornelia Huck <cohuck@...hat.com>,
        Claudio Imbrenda <imbrenda@...ux.ibm.com>
Subject: [RFC PATCH 1/3] KVM: Export kvm_make_all_cpus_request() for use in marking VMs as bugged

Export kvm_make_all_cpus_request() and hoist the request helper
declarations of request up to the KVM_REQ_* definitions in preparation
for adding a "VM bugged" framework.  The framework will add KVM_BUG()
and KVM_BUG_ON() as alternatives to full BUG()/BUG_ON() for cases where
KVM has definitely hit a bug (in itself or in silicon) and the VM is all
but guaranteed to be hosed.  Marking a VM bugged will trigger a request
to all vCPUs to allow arch code to forcefully evict each vCPU from its
run loop.

Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
---
 include/linux/kvm_host.h | 18 +++++++++---------
 virt/kvm/kvm_main.c      |  1 +
 2 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 05e3c2fb3ef7..1d70aeeb7ec3 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -154,6 +154,15 @@ static inline bool is_error_page(struct page *page)
 })
 #define KVM_ARCH_REQ(nr)           KVM_ARCH_REQ_FLAGS(nr, 0)
 
+bool kvm_make_vcpus_request_mask(struct kvm *kvm, unsigned int req,
+				 struct kvm_vcpu *except,
+				 unsigned long *vcpu_bitmap, cpumask_var_t tmp);
+bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req);
+bool kvm_make_all_cpus_request_except(struct kvm *kvm, unsigned int req,
+				      struct kvm_vcpu *except);
+bool kvm_make_cpus_request_mask(struct kvm *kvm, unsigned int req,
+				unsigned long *vcpu_bitmap);
+
 #define KVM_USERSPACE_IRQ_SOURCE_ID		0
 #define KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID	1
 
@@ -845,15 +854,6 @@ void kvm_mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc);
 void *kvm_mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc);
 #endif
 
-bool kvm_make_vcpus_request_mask(struct kvm *kvm, unsigned int req,
-				 struct kvm_vcpu *except,
-				 unsigned long *vcpu_bitmap, cpumask_var_t tmp);
-bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req);
-bool kvm_make_all_cpus_request_except(struct kvm *kvm, unsigned int req,
-				      struct kvm_vcpu *except);
-bool kvm_make_cpus_request_mask(struct kvm *kvm, unsigned int req,
-				unsigned long *vcpu_bitmap);
-
 long kvm_arch_dev_ioctl(struct file *filp,
 			unsigned int ioctl, unsigned long arg);
 long kvm_arch_vcpu_ioctl(struct file *filp,
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index cf88233b819a..bf3f333c7a19 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -306,6 +306,7 @@ bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req)
 {
 	return kvm_make_all_cpus_request_except(kvm, req, NULL);
 }
+EXPORT_SYMBOL_GPL(kvm_make_all_cpus_request);
 
 #ifndef CONFIG_HAVE_KVM_ARCH_TLB_FLUSH_ALL
 void kvm_flush_remote_tlbs(struct kvm *kvm)
-- 
2.28.0