Mixture of bitfields and types is weird and really not intuitive, remove bitfields and use typed data exclusively. Bitfields often result in inferior machine code. Link: https://lore.kernel.org/all/20240404101735.402feec8@jacob-builder/T/#mf66e34a82a48f4d8e2926b5581eff59a122de53a Suggested-by: Sean Christopherson <seanjc@xxxxxxxxxx> Suggested-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Signed-off-by: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx> --- v3: - Fix a bug where SN bit position was used as the mask, reported by Oliver Sang. - Add and use non-atomic helpers to manipulate SN bit - Use pi_test_sn() instead of open coding v2: - Replace bitfields, no more mix. --- arch/x86/include/asm/posted_intr.h | 21 ++++++++++++--------- arch/x86/kvm/vmx/posted_intr.c | 4 ++-- arch/x86/kvm/vmx/vmx.c | 2 +- 3 files changed, 15 insertions(+), 12 deletions(-) diff --git a/arch/x86/include/asm/posted_intr.h b/arch/x86/include/asm/posted_intr.h index acf237b2882e..20e31891de15 100644 --- a/arch/x86/include/asm/posted_intr.h +++ b/arch/x86/include/asm/posted_intr.h @@ -15,17 +15,9 @@ struct pi_desc { }; union { struct { - /* bit 256 - Outstanding Notification */ - u16 on : 1, - /* bit 257 - Suppress Notification */ - sn : 1, - /* bit 271:258 - Reserved */ - rsvd_1 : 14; - /* bit 279:272 - Notification Vector */ + u16 notifications; /* Suppress and outstanding bits */ u8 nv; - /* bit 287:280 - Reserved */ u8 rsvd_2; - /* bit 319:288 - Notification Destination */ u32 ndst; }; u64 control; @@ -88,4 +80,15 @@ static inline bool pi_test_sn(struct pi_desc *pi_desc) return test_bit(POSTED_INTR_SN, (unsigned long *)&pi_desc->control); } +/* Non-atomic helpers */ +static inline void __pi_set_sn(struct pi_desc *pi_desc) +{ + pi_desc->notifications |= BIT(POSTED_INTR_SN); +} + +static inline void __pi_clear_sn(struct pi_desc *pi_desc) +{ + pi_desc->notifications &= ~BIT(POSTED_INTR_SN); +} + #endif /* _X86_POSTED_INTR_H */ diff --git a/arch/x86/kvm/vmx/posted_intr.c b/arch/x86/kvm/vmx/posted_intr.c index af662312fd07..ec08fa3caf43 100644 --- a/arch/x86/kvm/vmx/posted_intr.c +++ b/arch/x86/kvm/vmx/posted_intr.c @@ -107,7 +107,7 @@ void vmx_vcpu_pi_load(struct kvm_vcpu *vcpu, int cpu) * handle task migration (@cpu != vcpu->cpu). */ new.ndst = dest; - new.sn = 0; + __pi_clear_sn(&new); /* * Restore the notification vector; in the blocking case, the @@ -157,7 +157,7 @@ static void pi_enable_wakeup_handler(struct kvm_vcpu *vcpu) &per_cpu(wakeup_vcpus_on_cpu, vcpu->cpu)); raw_spin_unlock(&per_cpu(wakeup_vcpus_on_cpu_lock, vcpu->cpu)); - WARN(pi_desc->sn, "PI descriptor SN field set before blocking"); + WARN(pi_test_sn(pi_desc), "PI descriptor SN field set before blocking"); old.control = READ_ONCE(pi_desc->control); do { diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index d94bb069bac9..f505745913c8 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -4843,7 +4843,7 @@ static void __vmx_vcpu_reset(struct kvm_vcpu *vcpu) * or POSTED_INTR_WAKEUP_VECTOR. */ vmx->pi_desc.nv = POSTED_INTR_VECTOR; - vmx->pi_desc.sn = 1; + __pi_set_sn(&vmx->pi_desc); } static void vmx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) -- 2.25.1
