From: Paolo Bonzini <pbonzini@redhat.com>
Date: Tue, 12 Dec 2017 17:41:34 +0100
Subject: KVM: introduce kvm_arch_vcpu_async_ioctl
Patch-mainline: v4.16-rc1
Git-commit: 5cb0944c0c66004c0d9006a7f0fba5782ae38f69
References: jsc#SLE-4084
After the vcpu_load/vcpu_put pushdown, the handling of asynchronous VCPU
ioctl is already much clearer in that it is obvious that they bypass
vcpu_load and vcpu_put.
However, it is still not perfect in that the different state of the VCPU
mutex is still hidden in the caller. Separate those ioctls into a new
function kvm_arch_vcpu_async_ioctl that returns -ENOIOCTLCMD for more
"traditional" synchronous ioctls.
Cc: James Hogan <jhogan@kernel.org>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Suggested-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Liang Yan <lyan@suse.com>
---
arch/mips/kvm/Kconfig | 1 +
arch/mips/kvm/mips.c | 15 ++++++++++++---
arch/powerpc/kvm/Kconfig | 1 +
arch/powerpc/kvm/powerpc.c | 14 +++++++++++---
arch/s390/kvm/Kconfig | 1 +
arch/s390/kvm/kvm-s390.c | 16 ++++++++++++----
include/linux/kvm_host.h | 12 ++++++++++++
virt/kvm/Kconfig | 3 +++
virt/kvm/kvm_main.c | 12 +++++-------
9 files changed, 58 insertions(+), 17 deletions(-)
--- a/arch/mips/kvm/Kconfig
+++ b/arch/mips/kvm/Kconfig
@@ -21,6 +21,7 @@ config KVM
select PREEMPT_NOTIFIERS
select ANON_INODES
select KVM_GENERIC_DIRTYLOG_READ_PROTECT
+ select HAVE_KVM_VCPU_ASYNC_IOCTL
select KVM_MMIO
select MMU_NOTIFIER
select SRCU
--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -903,12 +903,11 @@ static int kvm_vcpu_ioctl_enable_cap(str
return r;
}
-long kvm_arch_vcpu_ioctl(struct file *filp, unsigned int ioctl,
- unsigned long arg)
+long kvm_arch_vcpu_async_ioctl(struct file *filp, unsigned int ioctl,
+ unsigned long arg)
{
struct kvm_vcpu *vcpu = filp->private_data;
void __user *argp = (void __user *)arg;
- long r;
if (ioctl == KVM_INTERRUPT) {
struct kvm_mips_interrupt irq;
@@ -921,6 +920,16 @@ long kvm_arch_vcpu_ioctl(struct file *fi
return kvm_vcpu_ioctl_interrupt(vcpu, &irq);
}
+ return -ENOIOCTLCMD;
+}
+
+long kvm_arch_vcpu_ioctl(struct file *filp, unsigned int ioctl,
+ unsigned long arg)
+{
+ struct kvm_vcpu *vcpu = filp->private_data;
+ void __user *argp = (void __user *)arg;
+ long r;
+
vcpu_load(vcpu);
switch (ioctl) {
--- a/arch/powerpc/kvm/Kconfig
+++ b/arch/powerpc/kvm/Kconfig
@@ -21,6 +21,7 @@ config KVM
select PREEMPT_NOTIFIERS
select ANON_INODES
select HAVE_KVM_EVENTFD
+ select HAVE_KVM_VCPU_ASYNC_IOCTL
select SRCU
select KVM_VFIO
select IRQ_BYPASS_MANAGER
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -1612,12 +1612,11 @@ int kvm_arch_vcpu_ioctl_set_mpstate(stru
return -EINVAL;
}
-long kvm_arch_vcpu_ioctl(struct file *filp,
- unsigned int ioctl, unsigned long arg)
+long kvm_arch_vcpu_async_ioctl(struct file *filp,
+ unsigned int ioctl, unsigned long arg)
{
struct kvm_vcpu *vcpu = filp->private_data;
void __user *argp = (void __user *)arg;
- long r;
if (ioctl == KVM_INTERRUPT) {
struct kvm_interrupt irq;
@@ -1625,6 +1624,15 @@ long kvm_arch_vcpu_ioctl(struct file *fi
return -EFAULT;
return kvm_vcpu_ioctl_interrupt(vcpu, &irq);
}
+ return -ENOIOCTLCMD;
+}
+
+long kvm_arch_vcpu_ioctl(struct file *filp,
+ unsigned int ioctl, unsigned long arg)
+{
+ struct kvm_vcpu *vcpu = filp->private_data;
+ void __user *argp = (void __user *)arg;
+ long r;
vcpu_load(vcpu);
--- a/arch/s390/kvm/Kconfig
+++ b/arch/s390/kvm/Kconfig
@@ -22,6 +22,7 @@ config KVM
select PREEMPT_NOTIFIERS
select ANON_INODES
select HAVE_KVM_CPU_RELAX_INTERCEPT
+ select HAVE_KVM_VCPU_ASYNC_IOCTL
select HAVE_KVM_EVENTFD
select KVM_ASYNC_PF
select KVM_ASYNC_PF_SYNC
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -3742,13 +3742,11 @@ static long kvm_s390_guest_mem_op(struct
return r;
}
-long kvm_arch_vcpu_ioctl(struct file *filp,
- unsigned int ioctl, unsigned long arg)
+long kvm_arch_vcpu_async_ioctl(struct file *filp,
+ unsigned int ioctl, unsigned long arg)
{
struct kvm_vcpu *vcpu = filp->private_data;
void __user *argp = (void __user *)arg;
- int idx;
- long r;
switch (ioctl) {
case KVM_S390_IRQ: {
@@ -3769,6 +3767,16 @@ long kvm_arch_vcpu_ioctl(struct file *fi
return kvm_s390_inject_vcpu(vcpu, &s390irq);
}
}
+ return -ENOIOCTLCMD;
+}
+
+long kvm_arch_vcpu_ioctl(struct file *filp,
+ unsigned int ioctl, unsigned long arg)
+{
+ struct kvm_vcpu *vcpu = filp->private_data;
+ void __user *argp = (void __user *)arg;
+ int idx;
+ long r;
vcpu_load(vcpu);
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1260,4 +1260,16 @@ static inline bool vcpu_valid_wakeup(str
}
#endif /* CONFIG_HAVE_KVM_INVALID_WAKEUPS */
+#ifdef CONFIG_HAVE_KVM_VCPU_ASYNC_IOCTL
+long kvm_arch_vcpu_async_ioctl(struct file *filp,
+ unsigned int ioctl, unsigned long arg);
+#else
+static inline long kvm_arch_vcpu_async_ioctl(struct file *filp,
+ unsigned int ioctl,
+ unsigned long arg)
+{
+ return -ENOIOCTLCMD;
+}
+#endif /* CONFIG_HAVE_KVM_VCPU_ASYNC_IOCTL */
+
#endif
--- a/virt/kvm/Kconfig
+++ b/virt/kvm/Kconfig
@@ -50,3 +50,6 @@ config KVM_COMPAT
config HAVE_KVM_IRQ_BYPASS
bool
+
+config HAVE_KVM_VCPU_ASYNC_IOCTL
+ bool
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2586,15 +2586,13 @@ static long kvm_vcpu_ioctl(struct file *
if (unlikely(_IOC_TYPE(ioctl) != KVMIO))
return -EINVAL;
-#if defined(CONFIG_S390) || defined(CONFIG_PPC) || defined(CONFIG_MIPS)
/*
- * Special cases: vcpu ioctls that are asynchronous to vcpu execution,
- * so vcpu_load() would break it.
+ * Some architectures have vcpu ioctls that are asynchronous to vcpu
+ * execution; mutex_lock() would break them.
*/
- if (ioctl == KVM_S390_INTERRUPT || ioctl == KVM_S390_IRQ || ioctl == KVM_INTERRUPT)
- return kvm_arch_vcpu_ioctl(filp, ioctl, arg);
-#endif
-
+ r = kvm_arch_vcpu_async_ioctl(filp, ioctl, arg);
+ if (r != -ENOIOCTLCMD)
+ return r;
if (mutex_lock_killable(&vcpu->mutex))
return -EINTR;