diff mbox series

[v3,3/5] KVM: X86: Use APIC_DEST_* macros properly in kvm_lapic_irq.dest_mode

Message ID 20191202201314.543-4-peterx@redhat.com (mailing list archive)
State New, archived
Headers show
Series KVM: X86: Cleanups on dest_mode and headers | expand

Commit Message

Peter Xu Dec. 2, 2019, 8:13 p.m. UTC 
We were using either APIC_DEST_PHYSICAL|APIC_DEST_LOGICAL or 0|1 to
fill in kvm_lapic_irq.dest_mode.  It's fine only because in most cases
when we check against dest_mode it's against APIC_DEST_PHYSICAL (which
equals to 0).  However, that's not consistent.  We'll have problem
when we want to start checking against APIC_DEST_PHYSICAL, which does
not equals to 1.

This patch firstly introduces kvm_lapic_irq_dest_mode() helper to take
any boolean of destination mode and return the APIC_DEST_* macro.
Then, it replaces the 0|1 settings of irq.dest_mode with the helper.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 arch/x86/include/asm/kvm_host.h | 5 +++++
 arch/x86/kvm/ioapic.c           | 8 +++++---
 arch/x86/kvm/irq_comm.c         | 7 ++++---
 arch/x86/kvm/x86.c              | 2 +-
 4 files changed, 15 insertions(+), 7 deletions(-)

Comments

Vitaly Kuznetsov Dec. 3, 2019, 1:16 p.m. UTC | #1 
Peter Xu <peterx@redhat.com> writes:

> We were using either APIC_DEST_PHYSICAL|APIC_DEST_LOGICAL or 0|1 to
> fill in kvm_lapic_irq.dest_mode.  It's fine only because in most cases
> when we check against dest_mode it's against APIC_DEST_PHYSICAL (which
> equals to 0).  However, that's not consistent.  We'll have problem
> when we want to start checking against APIC_DEST_PHYSICAL

APIC_DEST_LOGICAL

> which does not equals to 1.
>
> This patch firstly introduces kvm_lapic_irq_dest_mode() helper to take
> any boolean of destination mode and return the APIC_DEST_* macro.
> Then, it replaces the 0|1 settings of irq.dest_mode with the helper.
>
> Signed-off-by: Peter Xu <peterx@redhat.com>
> ---
>  arch/x86/include/asm/kvm_host.h | 5 +++++
>  arch/x86/kvm/ioapic.c           | 8 +++++---
>  arch/x86/kvm/irq_comm.c         | 7 ++++---
>  arch/x86/kvm/x86.c              | 2 +-
>  4 files changed, 15 insertions(+), 7 deletions(-)
>
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index b79cd6aa4075..f815c97b1b57 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -1022,6 +1022,11 @@ struct kvm_lapic_irq {
>  	bool msi_redir_hint;
>  };
>  
> +static inline u16 kvm_lapic_irq_dest_mode(bool dest_mode)
> +{
> +	return dest_mode ? APIC_DEST_LOGICAL : APIC_DEST_PHYSICAL;
> +}
> +
>  struct kvm_x86_ops {
>  	int (*cpu_has_kvm_support)(void);          /* __init */
>  	int (*disabled_by_bios)(void);             /* __init */
> diff --git a/arch/x86/kvm/ioapic.c b/arch/x86/kvm/ioapic.c
> index 9fd2dd89a1c5..901d85237d1c 100644
> --- a/arch/x86/kvm/ioapic.c
> +++ b/arch/x86/kvm/ioapic.c
> @@ -331,7 +331,8 @@ static void ioapic_write_indirect(struct kvm_ioapic *ioapic, u32 val)
>  			irq.vector = e->fields.vector;
>  			irq.delivery_mode = e->fields.delivery_mode << 8;
>  			irq.dest_id = e->fields.dest_id;
> -			irq.dest_mode = e->fields.dest_mode;
> +			irq.dest_mode =
> +			    kvm_lapic_irq_dest_mode(e->fields.dest_mode);
>  			bitmap_zero(&vcpu_bitmap, 16);
>  			kvm_bitmap_or_dest_vcpus(ioapic->kvm, &irq,
>  						 &vcpu_bitmap);
> @@ -343,7 +344,8 @@ static void ioapic_write_indirect(struct kvm_ioapic *ioapic, u32 val)
>  				 * keep ioapic_handled_vectors synchronized.
>  				 */
>  				irq.dest_id = old_dest_id;
> -				irq.dest_mode = old_dest_mode;
> +				irq.dest_mode =
> +				    kvm_lapic_irq_dest_mode(e->fields.dest_mode);
>  				kvm_bitmap_or_dest_vcpus(ioapic->kvm, &irq,
>  							 &vcpu_bitmap);
>  			}
> @@ -369,7 +371,7 @@ static int ioapic_service(struct kvm_ioapic *ioapic, int irq, bool line_status)
>  
>  	irqe.dest_id = entry->fields.dest_id;
>  	irqe.vector = entry->fields.vector;
> -	irqe.dest_mode = entry->fields.dest_mode;
> +	irqe.dest_mode = kvm_lapic_irq_dest_mode(entry->fields.dest_mode);
>  	irqe.trig_mode = entry->fields.trig_mode;
>  	irqe.delivery_mode = entry->fields.delivery_mode << 8;
>  	irqe.level = 1;
> diff --git a/arch/x86/kvm/irq_comm.c b/arch/x86/kvm/irq_comm.c
> index 8ecd48d31800..5f59e5ebdbed 100644
> --- a/arch/x86/kvm/irq_comm.c
> +++ b/arch/x86/kvm/irq_comm.c
> @@ -52,8 +52,8 @@ int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src,
>  	unsigned long dest_vcpu_bitmap[BITS_TO_LONGS(KVM_MAX_VCPUS)];
>  	unsigned int dest_vcpus = 0;
>  
> -	if (irq->dest_mode == 0 && irq->dest_id == 0xff &&
> -			kvm_lowest_prio_delivery(irq)) {
> +	if (irq->dest_mode == APIC_DEST_PHYSICAL &&
> +	    irq->dest_id == 0xff && kvm_lowest_prio_delivery(irq)) {
>  		printk(KERN_INFO "kvm: apic: phys broadcast and lowest prio\n");
>  		irq->delivery_mode = APIC_DM_FIXED;
>  	}
> @@ -114,7 +114,8 @@ void kvm_set_msi_irq(struct kvm *kvm, struct kvm_kernel_irq_routing_entry *e,
>  		irq->dest_id |= MSI_ADDR_EXT_DEST_ID(e->msi.address_hi);
>  	irq->vector = (e->msi.data &
>  			MSI_DATA_VECTOR_MASK) >> MSI_DATA_VECTOR_SHIFT;
> -	irq->dest_mode = (1 << MSI_ADDR_DEST_MODE_SHIFT) & e->msi.address_lo;
> +	irq->dest_mode = kvm_lapic_irq_dest_mode(
> +	    (1 << MSI_ADDR_DEST_MODE_SHIFT) & e->msi.address_lo);

This usage is a bit fishy (I understand that it works, but),
kvm_lapic_irq_dest_mode()'s input is bool (0/1) but here we're passing
something different.

I'm not sure kvm_lapic_irq_dest_mode() is even needed here, but in case
it is I'd suggest to add '!!':

 kvm_lapic_irq_dest_mode(!!((1 << MSI_ADDR_DEST_MODE_SHIFT) & e->msi.address_lo))

to make things explicit. I don't like how it looks though.

>  	irq->trig_mode = (1 << MSI_DATA_TRIGGER_SHIFT) & e->msi.data;
>  	irq->delivery_mode = e->msi.data & 0x700;
>  	irq->msi_redir_hint = ((e->msi.address_lo
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 3ed167e039e5..3b00d662dc14 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -7356,7 +7356,7 @@ static void kvm_pv_kick_cpu_op(struct kvm *kvm, unsigned long flags, int apicid)
>  	struct kvm_lapic_irq lapic_irq;
>  
>  	lapic_irq.shorthand = 0;
> -	lapic_irq.dest_mode = 0;
> +	lapic_irq.dest_mode = APIC_DEST_PHYSICAL;
>  	lapic_irq.level = 0;
>  	lapic_irq.dest_id = apicid;
>  	lapic_irq.msi_redir_hint = false;
Peter Xu Dec. 3, 2019, 4:16 p.m. UTC | #2 
On Tue, Dec 03, 2019 at 02:16:01PM +0100, Vitaly Kuznetsov wrote:
> Peter Xu <peterx@redhat.com> writes:
> 
> > We were using either APIC_DEST_PHYSICAL|APIC_DEST_LOGICAL or 0|1 to
> > fill in kvm_lapic_irq.dest_mode.  It's fine only because in most cases
> > when we check against dest_mode it's against APIC_DEST_PHYSICAL (which
> > equals to 0).  However, that's not consistent.  We'll have problem
> > when we want to start checking against APIC_DEST_PHYSICAL
> 
> APIC_DEST_LOGICAL

Fixed.

> > +	irq->dest_mode = kvm_lapic_irq_dest_mode(
> > +	    (1 << MSI_ADDR_DEST_MODE_SHIFT) & e->msi.address_lo);
> 
> This usage is a bit fishy (I understand that it works, but),
> kvm_lapic_irq_dest_mode()'s input is bool (0/1) but here we're passing
> something different.
> 
> I'm not sure kvm_lapic_irq_dest_mode() is even needed here, but in case
> it is I'd suggest to add '!!':
> 
>  kvm_lapic_irq_dest_mode(!!((1 << MSI_ADDR_DEST_MODE_SHIFT) & e->msi.address_lo))
> 
> to make things explicit. I don't like how it looks though.

IMHO it's the same (converting uint to _Bool will be the same as "!!",
also A ? B : C will be another, so we probably wrote this three times,
each of them will translate to a similar pattern of "cmpl + setne" asm
code).  But sure I can add them if you prefer.

Thanks,
diff mbox series

Patch

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index b79cd6aa4075..f815c97b1b57 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1022,6 +1022,11 @@  struct kvm_lapic_irq {
 	bool msi_redir_hint;
 };
 
+static inline u16 kvm_lapic_irq_dest_mode(bool dest_mode)
+{
+	return dest_mode ? APIC_DEST_LOGICAL : APIC_DEST_PHYSICAL;
+}
+
 struct kvm_x86_ops {
 	int (*cpu_has_kvm_support)(void);          /* __init */
 	int (*disabled_by_bios)(void);             /* __init */
diff --git a/arch/x86/kvm/ioapic.c b/arch/x86/kvm/ioapic.c
index 9fd2dd89a1c5..901d85237d1c 100644
--- a/arch/x86/kvm/ioapic.c
+++ b/arch/x86/kvm/ioapic.c
@@ -331,7 +331,8 @@  static void ioapic_write_indirect(struct kvm_ioapic *ioapic, u32 val)
 			irq.vector = e->fields.vector;
 			irq.delivery_mode = e->fields.delivery_mode << 8;
 			irq.dest_id = e->fields.dest_id;
-			irq.dest_mode = e->fields.dest_mode;
+			irq.dest_mode =
+			    kvm_lapic_irq_dest_mode(e->fields.dest_mode);
 			bitmap_zero(&vcpu_bitmap, 16);
 			kvm_bitmap_or_dest_vcpus(ioapic->kvm, &irq,
 						 &vcpu_bitmap);
@@ -343,7 +344,8 @@  static void ioapic_write_indirect(struct kvm_ioapic *ioapic, u32 val)
 				 * keep ioapic_handled_vectors synchronized.
 				 */
 				irq.dest_id = old_dest_id;
-				irq.dest_mode = old_dest_mode;
+				irq.dest_mode =
+				    kvm_lapic_irq_dest_mode(e->fields.dest_mode);
 				kvm_bitmap_or_dest_vcpus(ioapic->kvm, &irq,
 							 &vcpu_bitmap);
 			}
@@ -369,7 +371,7 @@  static int ioapic_service(struct kvm_ioapic *ioapic, int irq, bool line_status)
 
 	irqe.dest_id = entry->fields.dest_id;
 	irqe.vector = entry->fields.vector;
-	irqe.dest_mode = entry->fields.dest_mode;
+	irqe.dest_mode = kvm_lapic_irq_dest_mode(entry->fields.dest_mode);
 	irqe.trig_mode = entry->fields.trig_mode;
 	irqe.delivery_mode = entry->fields.delivery_mode << 8;
 	irqe.level = 1;
diff --git a/arch/x86/kvm/irq_comm.c b/arch/x86/kvm/irq_comm.c
index 8ecd48d31800..5f59e5ebdbed 100644
--- a/arch/x86/kvm/irq_comm.c
+++ b/arch/x86/kvm/irq_comm.c
@@ -52,8 +52,8 @@  int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src,
 	unsigned long dest_vcpu_bitmap[BITS_TO_LONGS(KVM_MAX_VCPUS)];
 	unsigned int dest_vcpus = 0;
 
-	if (irq->dest_mode == 0 && irq->dest_id == 0xff &&
-			kvm_lowest_prio_delivery(irq)) {
+	if (irq->dest_mode == APIC_DEST_PHYSICAL &&
+	    irq->dest_id == 0xff && kvm_lowest_prio_delivery(irq)) {
 		printk(KERN_INFO "kvm: apic: phys broadcast and lowest prio\n");
 		irq->delivery_mode = APIC_DM_FIXED;
 	}
@@ -114,7 +114,8 @@  void kvm_set_msi_irq(struct kvm *kvm, struct kvm_kernel_irq_routing_entry *e,
 		irq->dest_id |= MSI_ADDR_EXT_DEST_ID(e->msi.address_hi);
 	irq->vector = (e->msi.data &
 			MSI_DATA_VECTOR_MASK) >> MSI_DATA_VECTOR_SHIFT;
-	irq->dest_mode = (1 << MSI_ADDR_DEST_MODE_SHIFT) & e->msi.address_lo;
+	irq->dest_mode = kvm_lapic_irq_dest_mode(
+	    (1 << MSI_ADDR_DEST_MODE_SHIFT) & e->msi.address_lo);
 	irq->trig_mode = (1 << MSI_DATA_TRIGGER_SHIFT) & e->msi.data;
 	irq->delivery_mode = e->msi.data & 0x700;
 	irq->msi_redir_hint = ((e->msi.address_lo
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 3ed167e039e5..3b00d662dc14 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -7356,7 +7356,7 @@  static void kvm_pv_kick_cpu_op(struct kvm *kvm, unsigned long flags, int apicid)
 	struct kvm_lapic_irq lapic_irq;
 
 	lapic_irq.shorthand = 0;
-	lapic_irq.dest_mode = 0;
+	lapic_irq.dest_mode = APIC_DEST_PHYSICAL;
 	lapic_irq.level = 0;
 	lapic_irq.dest_id = apicid;
 	lapic_irq.msi_redir_hint = false;