Re: [PATCH v1 1/1] KVM: s390: Don't cast parameter in bit operations

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 





On 24.02.22 12:36, Claudio Imbrenda wrote:
On Wed, 23 Feb 2022 18:44:20 +0200
Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> wrote:

While in this particular case it would not be a (critical) issue,
the pattern itself is bad and error prone in case somebody blindly
copies to their code.

Don't cast parameter to unsigned long pointer in the bit operations.
Instead copy to a local variable on stack of a proper type and use.

Fixes: d77e64141e32 ("KVM: s390: implement GISA IPM related primitives")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
---
  arch/s390/include/asm/kvm_host.h | 5 ++++-
  arch/s390/kvm/interrupt.c        | 6 +++---
  2 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index a22c9266ea05..f1c4a1b9b360 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -867,7 +867,10 @@ struct kvm_s390_gisa {
  			u8  reserved03[11];
  			u32 airq_count;
  		} g1;
-		struct {
+		struct { /* as a 256-bit bitmap */
+			DECLARE_BITMAP(b, 256);
+		} bitmap;
+		struct { /* as a set of 64-bit words */
  			u64 word[4];
  		} u64;
  	};
diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index db933c252dbc..04e055cbd080 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -304,7 +304,7 @@ static inline int gisa_in_alert_list(struct kvm_s390_gisa *gisa)
static inline void gisa_set_ipm_gisc(struct kvm_s390_gisa *gisa, u32 gisc)
  {
-	set_bit_inv(IPM_BIT_OFFSET + gisc, (unsigned long *) gisa);
+	set_bit_inv(IPM_BIT_OFFSET + gisc, gisa->bitmap.b);

wouldn't it be enough to pass gisa->u64.word here?
then no cast would be necessary


we do that at several places

arch/s390/kernel/processor.c: for_each_set_bit_inv(bit, (long *)&stfle_fac_list, MAX_FACILITY_BIT) arch/s390/kvm/interrupt.c: set_bit_inv(IPM_BIT_OFFSET + gisc, (unsigned long *) gisa); arch/s390/kvm/kvm-s390.c: set_bit_inv(vcpu->vcpu_id, (unsigned long *) sca->mcn); arch/s390/kvm/kvm-s390.c: set_bit_inv(vcpu->vcpu_id, (unsigned long *) &sca->mcn);


  }
static inline u8 gisa_get_ipm(struct kvm_s390_gisa *gisa)
@@ -314,12 +314,12 @@ static inline u8 gisa_get_ipm(struct kvm_s390_gisa *gisa)
static inline void gisa_clear_ipm_gisc(struct kvm_s390_gisa *gisa, u32 gisc)
  {
-	clear_bit_inv(IPM_BIT_OFFSET + gisc, (unsigned long *) gisa);
+	clear_bit_inv(IPM_BIT_OFFSET + gisc, gisa->bitmap.b);
  }
static inline int gisa_tac_ipm_gisc(struct kvm_s390_gisa *gisa, u32 gisc)
  {
-	return test_and_clear_bit_inv(IPM_BIT_OFFSET + gisc, (unsigned long *) gisa);
+	return test_and_clear_bit_inv(IPM_BIT_OFFSET + gisc, gisa->bitmap.b);
  }
static inline unsigned long pending_irqs_no_gisa(struct kvm_vcpu *vcpu)




[Index of Archives]     [KVM ARM]     [KVM ia64]     [KVM ppc]     [Virtualization Tools]     [Spice Development]     [Libvirt]     [Libvirt Users]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite Questions]     [Linux Kernel]     [Linux SCSI]     [XFree86]

  Powered by Linux