From 6d0386ea99875313fdfd074eb74013b6e3b48a76 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Wed, 27 Aug 2025 17:01:53 -0700 Subject: entry/kvm: KVM: Move KVM details related to signal/-EINTR into KVM proper Move KVM's morphing of pending signals into userspace exits into KVM proper, and drop the @vcpu param from xfer_to_guest_mode_handle_work(). How KVM responds to -EINTR is a detail that really belongs in KVM itself, and invoking kvm_handle_signal_exit() from kernel code creates an inverted module dependency. E.g. attempting to move kvm_handle_signal_exit() into kvm_main.c would generate an linker error when building kvm.ko as a module. Dropping KVM details will also converting the KVM "entry" code into a more generic virtualization framework so that it can be used when running as a Hyper-V root partition. Lastly, eliminating usage of "struct kvm_vcpu" outside of KVM is also nice to have for KVM x86 developers, as keeping the details of kvm_vcpu purely within KVM allows changing the layout of the structure without having to boot into a new kernel, e.g. allows rebuilding and reloading kvm.ko with a modified kvm_vcpu structure as part of debug/development. Signed-off-by: Sean Christopherson Reviewed-by: Thomas Gleixner Signed-off-by: Wei Liu --- kernel/entry/kvm.c | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-) (limited to 'kernel') diff --git a/kernel/entry/kvm.c b/kernel/entry/kvm.c index 8485f63863af..6fc762eaacca 100644 --- a/kernel/entry/kvm.c +++ b/kernel/entry/kvm.c @@ -1,17 +1,14 @@ // SPDX-License-Identifier: GPL-2.0 #include -#include -static int xfer_to_guest_mode_work(struct kvm_vcpu *vcpu, unsigned long ti_work) +static int xfer_to_guest_mode_work(unsigned long ti_work) { do { int ret; - if (ti_work & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL)) { - kvm_handle_signal_exit(vcpu); + if (ti_work & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL)) return -EINTR; - } if (ti_work & (_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY)) schedule(); @@ -19,7 +16,7 @@ static int xfer_to_guest_mode_work(struct kvm_vcpu *vcpu, unsigned long ti_work) if (ti_work & _TIF_NOTIFY_RESUME) resume_user_mode_work(NULL); - ret = arch_xfer_to_guest_mode_handle_work(vcpu, ti_work); + ret = arch_xfer_to_guest_mode_handle_work(ti_work); if (ret) return ret; @@ -28,7 +25,7 @@ static int xfer_to_guest_mode_work(struct kvm_vcpu *vcpu, unsigned long ti_work) return 0; } -int xfer_to_guest_mode_handle_work(struct kvm_vcpu *vcpu) +int xfer_to_guest_mode_handle_work(void) { unsigned long ti_work; @@ -44,6 +41,6 @@ int xfer_to_guest_mode_handle_work(struct kvm_vcpu *vcpu) if (!(ti_work & XFER_TO_GUEST_MODE_WORK)) return 0; - return xfer_to_guest_mode_work(vcpu, ti_work); + return xfer_to_guest_mode_work(ti_work); } EXPORT_SYMBOL_GPL(xfer_to_guest_mode_handle_work); -- cgit v1.2.3 From 9be7e1e320ff2e7db4b23c8ec5f599bbfac94ede Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Wed, 27 Aug 2025 17:01:54 -0700 Subject: entry: Rename "kvm" entry code assets to "virt" to genericize APIs Rename the "kvm" entry code files and Kconfigs to use generic "virt" nomenclature so that the code can be reused by other hypervisors (or rather, their root/dom0 partition drivers), without incorrectly suggesting the code somehow relies on and/or involves KVM. No functional change intended. Signed-off-by: Sean Christopherson Reviewed-by: Thomas Gleixner Reviewed-by: Joel Fernandes Signed-off-by: Wei Liu --- kernel/entry/Makefile | 2 +- kernel/entry/kvm.c | 46 ---------------------------------------------- kernel/entry/virt.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++ kernel/rcu/tree.c | 6 +++--- 4 files changed, 50 insertions(+), 50 deletions(-) delete mode 100644 kernel/entry/kvm.c create mode 100644 kernel/entry/virt.c (limited to 'kernel') diff --git a/kernel/entry/Makefile b/kernel/entry/Makefile index 77fcd83dd663..2333d70802e4 100644 --- a/kernel/entry/Makefile +++ b/kernel/entry/Makefile @@ -14,4 +14,4 @@ CFLAGS_common.o += -fno-stack-protector obj-$(CONFIG_GENERIC_IRQ_ENTRY) += common.o obj-$(CONFIG_GENERIC_SYSCALL) += syscall-common.o syscall_user_dispatch.o -obj-$(CONFIG_KVM_XFER_TO_GUEST_WORK) += kvm.o +obj-$(CONFIG_VIRT_XFER_TO_GUEST_WORK) += virt.o diff --git a/kernel/entry/kvm.c b/kernel/entry/kvm.c deleted file mode 100644 index 6fc762eaacca..000000000000 --- a/kernel/entry/kvm.c +++ /dev/null @@ -1,46 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0 - -#include - -static int xfer_to_guest_mode_work(unsigned long ti_work) -{ - do { - int ret; - - if (ti_work & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL)) - return -EINTR; - - if (ti_work & (_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY)) - schedule(); - - if (ti_work & _TIF_NOTIFY_RESUME) - resume_user_mode_work(NULL); - - ret = arch_xfer_to_guest_mode_handle_work(ti_work); - if (ret) - return ret; - - ti_work = read_thread_flags(); - } while (ti_work & XFER_TO_GUEST_MODE_WORK); - return 0; -} - -int xfer_to_guest_mode_handle_work(void) -{ - unsigned long ti_work; - - /* - * This is invoked from the outer guest loop with interrupts and - * preemption enabled. - * - * KVM invokes xfer_to_guest_mode_work_pending() with interrupts - * disabled in the inner loop before going into guest mode. No need - * to disable interrupts here. - */ - ti_work = read_thread_flags(); - if (!(ti_work & XFER_TO_GUEST_MODE_WORK)) - return 0; - - return xfer_to_guest_mode_work(ti_work); -} -EXPORT_SYMBOL_GPL(xfer_to_guest_mode_handle_work); diff --git a/kernel/entry/virt.c b/kernel/entry/virt.c new file mode 100644 index 000000000000..c52f99249763 --- /dev/null +++ b/kernel/entry/virt.c @@ -0,0 +1,46 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include + +static int xfer_to_guest_mode_work(unsigned long ti_work) +{ + do { + int ret; + + if (ti_work & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL)) + return -EINTR; + + if (ti_work & (_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY)) + schedule(); + + if (ti_work & _TIF_NOTIFY_RESUME) + resume_user_mode_work(NULL); + + ret = arch_xfer_to_guest_mode_handle_work(ti_work); + if (ret) + return ret; + + ti_work = read_thread_flags(); + } while (ti_work & XFER_TO_GUEST_MODE_WORK); + return 0; +} + +int xfer_to_guest_mode_handle_work(void) +{ + unsigned long ti_work; + + /* + * This is invoked from the outer guest loop with interrupts and + * preemption enabled. + * + * KVM invokes xfer_to_guest_mode_work_pending() with interrupts + * disabled in the inner loop before going into guest mode. No need + * to disable interrupts here. + */ + ti_work = read_thread_flags(); + if (!(ti_work & XFER_TO_GUEST_MODE_WORK)) + return 0; + + return xfer_to_guest_mode_work(ti_work); +} +EXPORT_SYMBOL_GPL(xfer_to_guest_mode_handle_work); diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 174ee243b349..995489b72535 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -573,7 +573,7 @@ void rcutorture_format_gp_seqs(unsigned long long seqs, char *cp, size_t len) } EXPORT_SYMBOL_GPL(rcutorture_format_gp_seqs); -#if defined(CONFIG_NO_HZ_FULL) && (!defined(CONFIG_GENERIC_ENTRY) || !defined(CONFIG_KVM_XFER_TO_GUEST_WORK)) +#if defined(CONFIG_NO_HZ_FULL) && (!defined(CONFIG_GENERIC_ENTRY) || !defined(CONFIG_VIRT_XFER_TO_GUEST_WORK)) /* * An empty function that will trigger a reschedule on * IRQ tail once IRQs get re-enabled on userspace/guest resume. @@ -602,7 +602,7 @@ noinstr void rcu_irq_work_resched(void) if (IS_ENABLED(CONFIG_GENERIC_ENTRY) && !(current->flags & PF_VCPU)) return; - if (IS_ENABLED(CONFIG_KVM_XFER_TO_GUEST_WORK) && (current->flags & PF_VCPU)) + if (IS_ENABLED(CONFIG_VIRT_XFER_TO_GUEST_WORK) && (current->flags & PF_VCPU)) return; instrumentation_begin(); @@ -611,7 +611,7 @@ noinstr void rcu_irq_work_resched(void) } instrumentation_end(); } -#endif /* #if defined(CONFIG_NO_HZ_FULL) && (!defined(CONFIG_GENERIC_ENTRY) || !defined(CONFIG_KVM_XFER_TO_GUEST_WORK)) */ +#endif /* #if defined(CONFIG_NO_HZ_FULL) && (!defined(CONFIG_GENERIC_ENTRY) || !defined(CONFIG_VIRT_XFER_TO_GUEST_WORK)) */ #ifdef CONFIG_PROVE_RCU /** -- cgit v1.2.3