From 0a0da3f92118950862700497bc7917f0fbf6a6e8 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Thu, 30 Oct 2025 13:09:24 -0700 Subject: KVM: Make support for kvm_arch_vcpu_async_ioctl() mandatory Implement kvm_arch_vcpu_async_ioctl() "natively" in x86 and arm64 instead of relying on an #ifdef'd stub, and drop HAVE_KVM_VCPU_ASYNC_IOCTL in anticipation of using the API on x86. Once x86 uses the API, providing a stub for one architecture and having all other architectures opt-in requires more code than simply implementing the API in the lone holdout. Eliminating the Kconfig will also reduce churn if the API is renamed in the future (spoiler alert). No functional change intended. Acked-by: Claudio Imbrenda Reviewed-by: Yan Zhao Tested-by: Yan Zhao Tested-by: Kai Huang Link: https://patch.msgid.link/20251030200951.3402865-2-seanjc@google.com Signed-off-by: Sean Christopherson --- virt/kvm/Kconfig | 3 --- 1 file changed, 3 deletions(-) (limited to 'virt') diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig index 5f0015c5dd95..267c7369c765 100644 --- a/virt/kvm/Kconfig +++ b/virt/kvm/Kconfig @@ -78,9 +78,6 @@ config HAVE_KVM_IRQ_BYPASS tristate select IRQ_BYPASS_MANAGER -config HAVE_KVM_VCPU_ASYNC_IOCTL - bool - config HAVE_KVM_VCPU_RUN_PID_CHANGE bool -- cgit v1.2.3 From 50efc2340a598da4bafa40bc01e18f8cf73a4ae3 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Thu, 30 Oct 2025 13:09:25 -0700 Subject: KVM: Rename kvm_arch_vcpu_async_ioctl() to kvm_arch_vcpu_unlocked_ioctl() Rename the "async" ioctl API to "unlocked" so that upcoming usage in x86's TDX code doesn't result in a massive misnomer. To avoid having to retry SEAMCALLs, TDX needs to acquire kvm->lock *and* all vcpu->mutex locks, and acquiring all of those locks after/inside the current vCPU's mutex is a non-starter. However, TDX also needs to acquire the vCPU's mutex and load the vCPU, i.e. the handling is very much not async to the vCPU. No functional change intended. Acked-by: Claudio Imbrenda Reviewed-by: Yan Zhao Tested-by: Yan Zhao Tested-by: Kai Huang Link: https://patch.msgid.link/20251030200951.3402865-3-seanjc@google.com Signed-off-by: Sean Christopherson --- arch/arm64/kvm/arm.c | 4 ++-- arch/loongarch/kvm/vcpu.c | 4 ++-- arch/mips/kvm/mips.c | 4 ++-- arch/powerpc/kvm/powerpc.c | 4 ++-- arch/riscv/kvm/vcpu.c | 4 ++-- arch/s390/kvm/kvm-s390.c | 4 ++-- arch/x86/kvm/x86.c | 4 ++-- include/linux/kvm_host.h | 4 ++-- virt/kvm/kvm_main.c | 6 +++--- 9 files changed, 19 insertions(+), 19 deletions(-) (limited to 'virt') diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index ef5bf57f79b7..cf23f6b07ec7 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -1835,8 +1835,8 @@ long kvm_arch_vcpu_ioctl(struct file *filp, return r; } -long kvm_arch_vcpu_async_ioctl(struct file *filp, unsigned int ioctl, - unsigned long arg) +long kvm_arch_vcpu_unlocked_ioctl(struct file *filp, unsigned int ioctl, + unsigned long arg) { return -ENOIOCTLCMD; } diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c index 30e3b089a596..9a5844e85fd3 100644 --- a/arch/loongarch/kvm/vcpu.c +++ b/arch/loongarch/kvm/vcpu.c @@ -1471,8 +1471,8 @@ int kvm_vcpu_ioctl_interrupt(struct kvm_vcpu *vcpu, struct kvm_interrupt *irq) return 0; } -long kvm_arch_vcpu_async_ioctl(struct file *filp, - unsigned int ioctl, unsigned long arg) +long kvm_arch_vcpu_unlocked_ioctl(struct file *filp, unsigned int ioctl, + unsigned long arg) { void __user *argp = (void __user *)arg; struct kvm_vcpu *vcpu = filp->private_data; diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c index a75587018f44..b0fb92fda4d4 100644 --- a/arch/mips/kvm/mips.c +++ b/arch/mips/kvm/mips.c @@ -895,8 +895,8 @@ static int kvm_vcpu_ioctl_enable_cap(struct kvm_vcpu *vcpu, return r; } -long kvm_arch_vcpu_async_ioctl(struct file *filp, unsigned int ioctl, - unsigned long arg) +long kvm_arch_vcpu_unlocked_ioctl(struct file *filp, unsigned int ioctl, + unsigned long arg) { struct kvm_vcpu *vcpu = filp->private_data; void __user *argp = (void __user *)arg; diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c index 2ba057171ebe..9a89a6d98f97 100644 --- a/arch/powerpc/kvm/powerpc.c +++ b/arch/powerpc/kvm/powerpc.c @@ -2028,8 +2028,8 @@ int kvm_arch_vcpu_ioctl_set_mpstate(struct kvm_vcpu *vcpu, return -EINVAL; } -long kvm_arch_vcpu_async_ioctl(struct file *filp, - unsigned int ioctl, unsigned long arg) +long kvm_arch_vcpu_unlocked_ioctl(struct file *filp, unsigned int ioctl, + unsigned long arg) { struct kvm_vcpu *vcpu = filp->private_data; void __user *argp = (void __user *)arg; diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c index bccb919ca615..a4bd6077eecc 100644 --- a/arch/riscv/kvm/vcpu.c +++ b/arch/riscv/kvm/vcpu.c @@ -238,8 +238,8 @@ vm_fault_t kvm_arch_vcpu_fault(struct kvm_vcpu *vcpu, struct vm_fault *vmf) return VM_FAULT_SIGBUS; } -long kvm_arch_vcpu_async_ioctl(struct file *filp, - unsigned int ioctl, unsigned long arg) +long kvm_arch_vcpu_unlocked_ioctl(struct file *filp, unsigned int ioctl, + unsigned long arg) { struct kvm_vcpu *vcpu = filp->private_data; void __user *argp = (void __user *)arg; diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 16ba04062854..8c4caa5f2fcd 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -5730,8 +5730,8 @@ static long kvm_s390_vcpu_memsida_op(struct kvm_vcpu *vcpu, return r; } -long kvm_arch_vcpu_async_ioctl(struct file *filp, - unsigned int ioctl, unsigned long arg) +long kvm_arch_vcpu_unlocked_ioctl(struct file *filp, unsigned int ioctl, + unsigned long arg) { struct kvm_vcpu *vcpu = filp->private_data; void __user *argp = (void __user *)arg; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index ca5ba2caf314..b85cb213a336 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -7240,8 +7240,8 @@ static int kvm_vm_ioctl_set_clock(struct kvm *kvm, void __user *argp) return 0; } -long kvm_arch_vcpu_async_ioctl(struct file *filp, unsigned int ioctl, - unsigned long arg) +long kvm_arch_vcpu_unlocked_ioctl(struct file *filp, unsigned int ioctl, + unsigned long arg) { return -ENOIOCTLCMD; } diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 7186b2ae4b57..d93f75b05ae2 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -1557,6 +1557,8 @@ long kvm_arch_dev_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg); long kvm_arch_vcpu_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg); +long kvm_arch_vcpu_unlocked_ioctl(struct file *filp, + unsigned int ioctl, unsigned long arg); vm_fault_t kvm_arch_vcpu_fault(struct kvm_vcpu *vcpu, struct vm_fault *vmf); int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext); @@ -2437,8 +2439,6 @@ static inline bool kvm_arch_no_poll(struct kvm_vcpu *vcpu) } #endif /* CONFIG_HAVE_KVM_NO_POLL */ -long kvm_arch_vcpu_async_ioctl(struct file *filp, - unsigned int ioctl, unsigned long arg); void kvm_arch_guest_memory_reclaimed(struct kvm *kvm); #ifdef CONFIG_HAVE_KVM_VCPU_RUN_PID_CHANGE diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index b7a0ae2a7b20..b7db1d5f71a8 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -4434,10 +4434,10 @@ static long kvm_vcpu_ioctl(struct file *filp, return r; /* - * Some architectures have vcpu ioctls that are asynchronous to vcpu - * execution; mutex_lock() would break them. + * Let arch code handle select vCPU ioctls without holding vcpu->mutex, + * e.g. to support ioctls that can run asynchronous to vCPU execution. */ - r = kvm_arch_vcpu_async_ioctl(filp, ioctl, arg); + r = kvm_arch_vcpu_unlocked_ioctl(filp, ioctl, arg); if (r != -ENOIOCTLCMD) return r; -- cgit v1.2.3