diff mbox

[v4,1/7] KVM: api: pass the devid in the msi routing entry

Message ID 1459759657-7402-2-git-send-email-eric.auger@linaro.org (mailing list archive)
State New, archived
Headers show

Commit Message

Eric Auger April 4, 2016, 8:47 a.m. UTC
On ARM, the MSI msg (address and data) comes along with
out-of-band device ID information. The device ID encodes the
device that writes the MSI msg. Let's convey the device id in
kvm_irq_routing_msi and use KVM_MSI_VALID_DEVID flag value in
kvm_irq_routing_entry to indicate the msi devid is populated.

Signed-off-by: Eric Auger <eric.auger@linaro.org>

---
v2 -> v3:
- replace usage of KVM_IRQ_ROUTING_EXTENDED_MSI type by
  usage of KVM_MSI_VALID_DEVID flag
- add note about KVM_CAP_MSI_DEVID capability

v1 -> v2:
- devid id passed in kvm_irq_routing_msi instead of in
  kvm_irq_routing_entry

RFC -> PATCH
- remove kvm_irq_routing_extended_msi and use union instead
---
 Documentation/virtual/kvm/api.txt | 18 ++++++++++++++++--
 include/uapi/linux/kvm.h          |  5 ++++-
 2 files changed, 20 insertions(+), 3 deletions(-)

Comments

Christoffer Dall April 14, 2016, 12:04 p.m. UTC | #1
On Mon, Apr 04, 2016 at 10:47:31AM +0200, Eric Auger wrote:
> On ARM, the MSI msg (address and data) comes along with
> out-of-band device ID information. The device ID encodes the
> device that writes the MSI msg. Let's convey the device id in
> kvm_irq_routing_msi and use KVM_MSI_VALID_DEVID flag value in
> kvm_irq_routing_entry to indicate the msi devid is populated.
> 
> Signed-off-by: Eric Auger <eric.auger@linaro.org>
> 
> ---
> v2 -> v3:
> - replace usage of KVM_IRQ_ROUTING_EXTENDED_MSI type by
>   usage of KVM_MSI_VALID_DEVID flag
> - add note about KVM_CAP_MSI_DEVID capability
> 
> v1 -> v2:
> - devid id passed in kvm_irq_routing_msi instead of in
>   kvm_irq_routing_entry
> 
> RFC -> PATCH
> - remove kvm_irq_routing_extended_msi and use union instead
> ---
>  Documentation/virtual/kvm/api.txt | 18 ++++++++++++++++--
>  include/uapi/linux/kvm.h          |  5 ++++-
>  2 files changed, 20 insertions(+), 3 deletions(-)
> 
> diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
> index 536f19b..c436bb6 100644
> --- a/Documentation/virtual/kvm/api.txt
> +++ b/Documentation/virtual/kvm/api.txt
> @@ -1462,7 +1462,10 @@ struct kvm_irq_routing_entry {
>  #define KVM_IRQ_ROUTING_S390_ADAPTER 3
>  #define KVM_IRQ_ROUTING_HV_SINT 4
>  
> -No flags are specified so far, the corresponding field must be set to zero.
> +flags:
> +- KVM_MSI_VALID_DEVID: used along with KVM_IRQ_ROUTING_MSI
> +  routing entry type, it tells the msi devid contains a valid value.

s/it tells the msi devid/specifies that the devid field/

> +- zero otherwise
>  
>  struct kvm_irq_routing_irqchip {
>  	__u32 irqchip;
> @@ -1473,9 +1476,20 @@ struct kvm_irq_routing_msi {
>  	__u32 address_lo;
>  	__u32 address_hi;
>  	__u32 data;
> -	__u32 pad;
> +	union {
> +		__u32 pad;
> +		__u32 devid;
> +	};
>  };
>  
> +devid: If KVM_MSI_VALID_DEVID is set, contains a unique device identifier
> +       for the device that wrote the MSI message.
> +       For PCI, this is usually a BFD identifier in the lower 16 bits.
> +
> +The per-VM KVM_CAP_MSI_DEVID capability advertises the need to provide

"the need to" or "the possibility to"?  Is there ever a situation where
KVM_CAP_MSI_DEVID is set but you don't need to provide a device ID and
set the flag?

> +the device ID. If this capability is not set, userland cannot rely on
> +the kernel to allow the KVM_MSI_VALID_DEVID flag being set.
> +
>  struct kvm_irq_routing_s390_adapter {
>  	__u64 ind_addr;
>  	__u64 summary_addr;
> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
> index 6a02871..52a973f 100644
> --- a/include/uapi/linux/kvm.h
> +++ b/include/uapi/linux/kvm.h
> @@ -865,7 +865,10 @@ struct kvm_irq_routing_msi {
>  	__u32 address_lo;
>  	__u32 address_hi;
>  	__u32 data;
> -	__u32 pad;
> +	union {
> +		__u32 pad;
> +		__u32 devid;
> +	};
>  };
>  
>  struct kvm_irq_routing_s390_adapter {
> -- 
> 1.9.1
> 
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Eric Auger April 21, 2016, 1:31 p.m. UTC | #2
Christoffer,
On 04/14/2016 02:04 PM, Christoffer Dall wrote:
> On Mon, Apr 04, 2016 at 10:47:31AM +0200, Eric Auger wrote:
>> On ARM, the MSI msg (address and data) comes along with
>> out-of-band device ID information. The device ID encodes the
>> device that writes the MSI msg. Let's convey the device id in
>> kvm_irq_routing_msi and use KVM_MSI_VALID_DEVID flag value in
>> kvm_irq_routing_entry to indicate the msi devid is populated.
>>
>> Signed-off-by: Eric Auger <eric.auger@linaro.org>
>>
>> ---
>> v2 -> v3:
>> - replace usage of KVM_IRQ_ROUTING_EXTENDED_MSI type by
>>   usage of KVM_MSI_VALID_DEVID flag
>> - add note about KVM_CAP_MSI_DEVID capability
>>
>> v1 -> v2:
>> - devid id passed in kvm_irq_routing_msi instead of in
>>   kvm_irq_routing_entry
>>
>> RFC -> PATCH
>> - remove kvm_irq_routing_extended_msi and use union instead
>> ---
>>  Documentation/virtual/kvm/api.txt | 18 ++++++++++++++++--
>>  include/uapi/linux/kvm.h          |  5 ++++-
>>  2 files changed, 20 insertions(+), 3 deletions(-)
>>
>> diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
>> index 536f19b..c436bb6 100644
>> --- a/Documentation/virtual/kvm/api.txt
>> +++ b/Documentation/virtual/kvm/api.txt
>> @@ -1462,7 +1462,10 @@ struct kvm_irq_routing_entry {
>>  #define KVM_IRQ_ROUTING_S390_ADAPTER 3
>>  #define KVM_IRQ_ROUTING_HV_SINT 4
>>  
>> -No flags are specified so far, the corresponding field must be set to zero.
>> +flags:
>> +- KVM_MSI_VALID_DEVID: used along with KVM_IRQ_ROUTING_MSI
>> +  routing entry type, it tells the msi devid contains a valid value.
> 
> s/it tells the msi devid/specifies that the devid field/
ok
> 
>> +- zero otherwise
>>  
>>  struct kvm_irq_routing_irqchip {
>>  	__u32 irqchip;
>> @@ -1473,9 +1476,20 @@ struct kvm_irq_routing_msi {
>>  	__u32 address_lo;
>>  	__u32 address_hi;
>>  	__u32 data;
>> -	__u32 pad;
>> +	union {
>> +		__u32 pad;
>> +		__u32 devid;
>> +	};
>>  };
>>  
>> +devid: If KVM_MSI_VALID_DEVID is set, contains a unique device identifier
>> +       for the device that wrote the MSI message.
>> +       For PCI, this is usually a BFD identifier in the lower 16 bits.
>> +
>> +The per-VM KVM_CAP_MSI_DEVID capability advertises the need to provide
> 
> "the need to" or "the possibility to"?  Is there ever a situation where
> KVM_CAP_MSI_DEVID is set but you don't need to provide a device ID and
> set the flag?
I could replace by "requirement":
if it is not requested to pass a devid, we don't set the flag. If it is
we pass it.

if the user fails passing the devid and this ends up in the in-kernel
ITS emul, injection will fail.

Thanks

Eric
> 
>> +the device ID. If this capability is not set, userland cannot rely on
>> +the kernel to allow the KVM_MSI_VALID_DEVID flag being set.
>> +
>>  struct kvm_irq_routing_s390_adapter {
>>  	__u64 ind_addr;
>>  	__u64 summary_addr;
>> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
>> index 6a02871..52a973f 100644
>> --- a/include/uapi/linux/kvm.h
>> +++ b/include/uapi/linux/kvm.h
>> @@ -865,7 +865,10 @@ struct kvm_irq_routing_msi {
>>  	__u32 address_lo;
>>  	__u32 address_hi;
>>  	__u32 data;
>> -	__u32 pad;
>> +	union {
>> +		__u32 pad;
>> +		__u32 devid;
>> +	};
>>  };
>>  
>>  struct kvm_irq_routing_s390_adapter {
>> -- 
>> 1.9.1
>>

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diff mbox

Patch

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 536f19b..c436bb6 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -1462,7 +1462,10 @@  struct kvm_irq_routing_entry {
 #define KVM_IRQ_ROUTING_S390_ADAPTER 3
 #define KVM_IRQ_ROUTING_HV_SINT 4
 
-No flags are specified so far, the corresponding field must be set to zero.
+flags:
+- KVM_MSI_VALID_DEVID: used along with KVM_IRQ_ROUTING_MSI
+  routing entry type, it tells the msi devid contains a valid value.
+- zero otherwise
 
 struct kvm_irq_routing_irqchip {
 	__u32 irqchip;
@@ -1473,9 +1476,20 @@  struct kvm_irq_routing_msi {
 	__u32 address_lo;
 	__u32 address_hi;
 	__u32 data;
-	__u32 pad;
+	union {
+		__u32 pad;
+		__u32 devid;
+	};
 };
 
+devid: If KVM_MSI_VALID_DEVID is set, contains a unique device identifier
+       for the device that wrote the MSI message.
+       For PCI, this is usually a BFD identifier in the lower 16 bits.
+
+The per-VM KVM_CAP_MSI_DEVID capability advertises the need to provide
+the device ID. If this capability is not set, userland cannot rely on
+the kernel to allow the KVM_MSI_VALID_DEVID flag being set.
+
 struct kvm_irq_routing_s390_adapter {
 	__u64 ind_addr;
 	__u64 summary_addr;
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 6a02871..52a973f 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -865,7 +865,10 @@  struct kvm_irq_routing_msi {
 	__u32 address_lo;
 	__u32 address_hi;
 	__u32 data;
-	__u32 pad;
+	union {
+		__u32 pad;
+		__u32 devid;
+	};
 };
 
 struct kvm_irq_routing_s390_adapter {