lkml.org 
[lkml]   [2021]   [Sep]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    Date
    SubjectRe: [PATCH v3 08/12] KVM: arm64: selftests: Add light-weight spinlock support
    On Wed, Sep 1, 2021 at 2:14 PM Raghavendra Rao Ananta
    <rananta@google.com> wrote:
    >
    > Add a simpler version of spinlock support for ARM64 for
    > the guests to use.
    >
    > The implementation is loosely based on the spinlock
    > implementation in kvm-unit-tests.
    >
    > Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
    > ---
    > tools/testing/selftests/kvm/Makefile | 2 +-
    > .../selftests/kvm/include/aarch64/spinlock.h | 13 +++++++++
    > .../selftests/kvm/lib/aarch64/spinlock.c | 27 +++++++++++++++++++
    > 3 files changed, 41 insertions(+), 1 deletion(-)
    > create mode 100644 tools/testing/selftests/kvm/include/aarch64/spinlock.h
    > create mode 100644 tools/testing/selftests/kvm/lib/aarch64/spinlock.c
    >
    > diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
    > index 5d05801ab816..61f0d376af99 100644
    > --- a/tools/testing/selftests/kvm/Makefile
    > +++ b/tools/testing/selftests/kvm/Makefile
    > @@ -35,7 +35,7 @@ endif
    >
    > LIBKVM = lib/assert.c lib/elf.c lib/io.c lib/kvm_util.c lib/rbtree.c lib/sparsebit.c lib/test_util.c lib/guest_modes.c lib/perf_test_util.c
    > LIBKVM_x86_64 = lib/x86_64/apic.c lib/x86_64/processor.c lib/x86_64/vmx.c lib/x86_64/svm.c lib/x86_64/ucall.c lib/x86_64/handlers.S
    > -LIBKVM_aarch64 = lib/aarch64/processor.c lib/aarch64/ucall.c lib/aarch64/handlers.S
    > +LIBKVM_aarch64 = lib/aarch64/processor.c lib/aarch64/ucall.c lib/aarch64/handlers.S lib/aarch64/spinlock.c
    > LIBKVM_s390x = lib/s390x/processor.c lib/s390x/ucall.c lib/s390x/diag318_test_handler.c
    >
    > TEST_GEN_PROGS_x86_64 = x86_64/cr4_cpuid_sync_test
    > diff --git a/tools/testing/selftests/kvm/include/aarch64/spinlock.h b/tools/testing/selftests/kvm/include/aarch64/spinlock.h
    > new file mode 100644
    > index 000000000000..cf0984106d14
    > --- /dev/null
    > +++ b/tools/testing/selftests/kvm/include/aarch64/spinlock.h
    > @@ -0,0 +1,13 @@
    > +/* SPDX-License-Identifier: GPL-2.0 */
    > +
    > +#ifndef SELFTEST_KVM_ARM64_SPINLOCK_H
    > +#define SELFTEST_KVM_ARM64_SPINLOCK_H
    > +
    > +struct spinlock {
    > + int v;
    > +};
    > +
    > +extern void spin_lock(struct spinlock *lock);
    > +extern void spin_unlock(struct spinlock *lock);
    > +
    > +#endif /* SELFTEST_KVM_ARM64_SPINLOCK_H */
    > diff --git a/tools/testing/selftests/kvm/lib/aarch64/spinlock.c b/tools/testing/selftests/kvm/lib/aarch64/spinlock.c
    > new file mode 100644
    > index 000000000000..6d66a3dac237
    > --- /dev/null
    > +++ b/tools/testing/selftests/kvm/lib/aarch64/spinlock.c
    > @@ -0,0 +1,27 @@
    > +// SPDX-License-Identifier: GPL-2.0
    > +/*
    > + * ARM64 Spinlock support
    > + */
    > +#include <stdint.h>
    > +
    > +#include "spinlock.h"
    > +
    > +void spin_lock(struct spinlock *lock)
    > +{
    > + uint32_t val, res;

    nit: use 'int' to match the lock value type.

    > +
    > + asm volatile(
    > + "1: ldaxr %w0, [%2]\n"
    > + " cbnz %w0, 1b\n"
    > + " mov %w0, #1\n"
    > + " stxr %w1, %w0, [%2]\n"
    > + " cbnz %w1, 1b\n"
    > + : "=&r" (val), "=&r" (res)
    > + : "r" (&lock->v)
    > + : "memory");
    > +}
    > +
    > +void spin_unlock(struct spinlock *lock)
    > +{
    > + asm volatile("stlr wzr, [%0]\n" : : "r" (&lock->v) : "memory");
    > +}
    > --
    > 2.33.0.153.gba50c8fa24-goog
    >

    Otherwise, LGTM.

    Reviewed-by: Oliver Upton <oupton@google.com>

    \
     
     \ /
      Last update: 2021-09-02 23:08    [W:4.088 / U:0.052 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site