| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <20251017111353.0d13af74@p-imbrenda>
Date: Fri, 17 Oct 2025 11:13:53 +0200
From: Claudio Imbrenda <imbrenda@...ux.ibm.com>
To: Sean Christopherson <seanjc@...gle.com>
Cc: Marc Zyngier <maz@...nel.org>, Oliver Upton <oliver.upton@...ux.dev>,
Tianrui Zhao <zhaotianrui@...ngson.cn>, Bibo Mao <maobibo@...ngson.cn>,
Huacai Chen <chenhuacai@...nel.org>,
Madhavan Srinivasan
<maddy@...ux.ibm.com>,
Anup Patel <anup@...infault.org>, Paul Walmsley
<pjw@...nel.org>,
Palmer Dabbelt <palmer@...belt.com>,
Albert Ou
<aou@...s.berkeley.edu>,
Christian Borntraeger <borntraeger@...ux.ibm.com>,
Janosch Frank <frankja@...ux.ibm.com>,
Paolo Bonzini <pbonzini@...hat.com>,
"Kirill A. Shutemov" <kas@...nel.org>,
linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.linux.dev,
kvm@...r.kernel.org, loongarch@...ts.linux.dev,
linux-mips@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
kvm-riscv@...ts.infradead.org, linux-riscv@...ts.infradead.org,
x86@...nel.org, linux-coco@...ts.linux.dev,
linux-kernel@...r.kernel.org, Ira Weiny
<ira.weiny@...el.com>,
Kai Huang <kai.huang@...el.com>, Michael Roth
<michael.roth@....com>,
Yan Zhao <yan.y.zhao@...el.com>,
Vishal Annapurve
<vannapurve@...gle.com>,
Rick Edgecombe <rick.p.edgecombe@...el.com>,
Ackerley Tng <ackerleytng@...gle.com>,
Binbin Wu
<binbin.wu@...ux.intel.com>
Subject: Re: [PATCH v3 02/25] KVM: Rename kvm_arch_vcpu_async_ioctl() to
kvm_arch_vcpu_unlocked_ioctl()
On Thu, 16 Oct 2025 17:32:20 -0700
Sean Christopherson <seanjc@...gle.com> wrote:
> 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.
>
> Signed-off-by: Sean Christopherson <seanjc@...gle.com>
Acked-by: Claudio Imbrenda <imbrenda@...ux.ibm.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 785aaaee6a5d..e8d654024608 100644
> --- a/arch/arm64/kvm/arm.c
> +++ b/arch/arm64/kvm/arm.c
> @@ -1828,8 +1828,8 @@ 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;
>
Powered by blists - more mailing lists