[PATCH v4 02/28] KVM: Rename kvm_arch_vcpu_async_ioctl() to kvm_arch_vcpu_unlocked_ioctl()

From: Sean Christopherson <seanjc@google.com>
To: Marc Zyngier <maz@kernel.org>,
	Oliver Upton <oliver.upton@linux.dev>,
	 Tianrui Zhao <zhaotianrui@loongson.cn>,
	Bibo Mao <maobibo@loongson.cn>,
	 Huacai Chen <chenhuacai@kernel.org>,
	Madhavan Srinivasan <maddy@linux.ibm.com>,
	 Anup Patel <anup@brainfault.org>, Paul Walmsley <pjw@kernel.org>,
	 Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	 Christian Borntraeger <borntraeger@linux.ibm.com>,
	Janosch Frank <frankja@linux.ibm.com>,
	 Claudio Imbrenda <imbrenda@linux.ibm.com>,
	Sean Christopherson <seanjc@google.com>,
	 Paolo Bonzini <pbonzini@redhat.com>,
	"Kirill A. Shutemov" <kas@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev,
	 kvm@vger.kernel.org, loongarch@lists.linux.dev,
	linux-mips@vger.kernel.org,  linuxppc-dev@lists.ozlabs.org,
	kvm-riscv@lists.infradead.org,  linux-riscv@lists.infradead.org,
	x86@kernel.org, linux-coco@lists.linux.dev,
	 linux-kernel@vger.kernel.org, Ira Weiny <ira.weiny@intel.com>,
	 Kai Huang <kai.huang@intel.com>,
	Binbin Wu <binbin.wu@linux.intel.com>,
	 Michael Roth <michael.roth@amd.com>,
	Yan Zhao <yan.y.zhao@intel.com>,
	 Vishal Annapurve <vannapurve@google.com>,
	Rick Edgecombe <rick.p.edgecombe@intel.com>,
	 Ackerley Tng <ackerleytng@google.com>
Subject: [PATCH v4 02/28] KVM: Rename kvm_arch_vcpu_async_ioctl() to kvm_arch_vcpu_unlocked_ioctl()
Date: Thu, 30 Oct 2025 13:09:25 -0700	[thread overview]
Message-ID: <20251030200951.3402865-3-seanjc@google.com> (raw)
In-Reply-To: <20251030200951.3402865-1-seanjc@google.com>

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 <imbrenda@linux.ibm.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 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(-)

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 4845e5739436..9eca084bdcbe 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;
 
-- 
2.51.1.930.gacf6e81ea2-goog

