diff mbox series

[v2,20/30] KVM: s390: pci: provide routines for enabling/disabling IOAT assist

Message ID 20220114203145.242984-21-mjrosato@linux.ibm.com (mailing list archive)
State New, archived
Headers show
Series KVM: s390: enable zPCI for interpretive execution | expand

Commit Message

Matthew Rosato Jan. 14, 2022, 8:31 p.m. UTC 
These routines will be wired into the vfio_pci_zdev ioctl handlers to
respond to requests to enable / disable a device for PCI I/O Address
Translation assistance.

Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
---
 arch/s390/include/asm/kvm_pci.h |  15 ++++
 arch/s390/include/asm/pci_dma.h |   2 +
 arch/s390/kvm/pci.c             | 139 ++++++++++++++++++++++++++++++++
 arch/s390/kvm/pci.h             |   2 +
 4 files changed, 158 insertions(+)

Comments

Pierre Morel Jan. 25, 2022, 1:29 p.m. UTC | #1 
On 1/14/22 21:31, Matthew Rosato wrote:
> These routines will be wired into the vfio_pci_zdev ioctl handlers to
> respond to requests to enable / disable a device for PCI I/O Address
> Translation assistance.
> 
> Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
> ---
>   arch/s390/include/asm/kvm_pci.h |  15 ++++
>   arch/s390/include/asm/pci_dma.h |   2 +
>   arch/s390/kvm/pci.c             | 139 ++++++++++++++++++++++++++++++++
>   arch/s390/kvm/pci.h             |   2 +
>   4 files changed, 158 insertions(+)
> 
> diff --git a/arch/s390/include/asm/kvm_pci.h b/arch/s390/include/asm/kvm_pci.h
> index 01fe14fffd7a..770849f13a70 100644
> --- a/arch/s390/include/asm/kvm_pci.h
> +++ b/arch/s390/include/asm/kvm_pci.h
> @@ -16,11 +16,21 @@
>   #include <linux/kvm_host.h>
>   #include <linux/kvm.h>
>   #include <linux/pci.h>
> +#include <linux/mutex.h>
>   #include <asm/pci_insn.h>
> +#include <asm/pci_dma.h>
> +
> +struct kvm_zdev_ioat {
> +	unsigned long *head[ZPCI_TABLE_PAGES];
> +	unsigned long **seg;
> +	unsigned long ***pt;
> +	struct mutex lock;

Can we please rename the mutex ioat_lock to have a unique name easy to 
follow for maintenance.
Can you please add a description about when the lock should be used?

> +};
>   
>   struct kvm_zdev {
>   	struct zpci_dev *zdev;
>   	struct kvm *kvm;
> +	struct kvm_zdev_ioat ioat;
>   	struct zpci_fib fib;
>   };
>   
> @@ -33,6 +43,11 @@ int kvm_s390_pci_aif_enable(struct zpci_dev *zdev, struct zpci_fib *fib,
>   			    bool assist);
>   int kvm_s390_pci_aif_disable(struct zpci_dev *zdev);
>   
> +int kvm_s390_pci_ioat_probe(struct zpci_dev *zdev);
> +int kvm_s390_pci_ioat_enable(struct zpci_dev *zdev, u64 iota);
> +int kvm_s390_pci_ioat_disable(struct zpci_dev *zdev);
> +u8 kvm_s390_pci_get_dtsm(struct zpci_dev *zdev);
> +
>   int kvm_s390_pci_interp_probe(struct zpci_dev *zdev);
>   int kvm_s390_pci_interp_enable(struct zpci_dev *zdev);
>   int kvm_s390_pci_interp_disable(struct zpci_dev *zdev);
> diff --git a/arch/s390/include/asm/pci_dma.h b/arch/s390/include/asm/pci_dma.h
> index 91e63426bdc5..69e616d0712c 100644
> --- a/arch/s390/include/asm/pci_dma.h
> +++ b/arch/s390/include/asm/pci_dma.h
> @@ -50,6 +50,8 @@ enum zpci_ioat_dtype {
>   #define ZPCI_TABLE_ALIGN		ZPCI_TABLE_SIZE
>   #define ZPCI_TABLE_ENTRY_SIZE		(sizeof(unsigned long))
>   #define ZPCI_TABLE_ENTRIES		(ZPCI_TABLE_SIZE / ZPCI_TABLE_ENTRY_SIZE)
> +#define ZPCI_TABLE_PAGES		(ZPCI_TABLE_SIZE >> PAGE_SHIFT)
> +#define ZPCI_TABLE_ENTRIES_PAGES	(ZPCI_TABLE_ENTRIES * ZPCI_TABLE_PAGES)
>   
>   #define ZPCI_TABLE_BITS			11
>   #define ZPCI_PT_BITS			8
> diff --git a/arch/s390/kvm/pci.c b/arch/s390/kvm/pci.c
> index 7ed9abc476b6..39c13c25a700 100644
> --- a/arch/s390/kvm/pci.c
> +++ b/arch/s390/kvm/pci.c
> @@ -13,12 +13,15 @@
>   #include <asm/pci.h>
>   #include <asm/pci_insn.h>
>   #include <asm/pci_io.h>
> +#include <asm/pci_dma.h>
>   #include <asm/sclp.h>
>   #include "pci.h"
>   #include "kvm-s390.h"
>   
>   struct zpci_aift *aift;
>   
> +#define shadow_ioat_init zdev->kzdev->ioat.head[0]
> +
>   static inline int __set_irq_noiib(u16 ctl, u8 isc)
>   {
>   	union zpci_sic_iib iib = {{0}};
> @@ -344,6 +347,135 @@ int kvm_s390_pci_aif_disable(struct zpci_dev *zdev)
>   }
>   EXPORT_SYMBOL_GPL(kvm_s390_pci_aif_disable);
>   
> +int kvm_s390_pci_ioat_probe(struct zpci_dev *zdev)
> +{
> +	/* Must have a KVM association registered */

may be add something like : "The ioat structure is embeded in kzdev"

> +	if (!zdev->kzdev || !zdev->kzdev->kvm)

Why do we need to check for kvm ?
Having kzdev is already tested by the unique caller.

> +		return -EINVAL;
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(kvm_s390_pci_ioat_probe);
> +
> +int kvm_s390_pci_ioat_enable(struct zpci_dev *zdev, u64 iota)
> +{
> +	gpa_t gpa = (gpa_t)(iota & ZPCI_RTE_ADDR_MASK);
> +	struct kvm_zdev_ioat *ioat;
> +	struct page *page;
> +	struct kvm *kvm;
> +	unsigned int idx;
> +	void *iaddr;
> +	int i, rc = 0;

no need to initialize rc

> +
> +	if (shadow_ioat_init)
> +		return -EINVAL;
> +
> +	/* Ensure supported type specified */
> +	if ((iota & ZPCI_IOTA_RTTO_FLAG) != ZPCI_IOTA_RTTO_FLAG)
> +		return -EINVAL;
> +
> +	kvm = zdev->kzdev->kvm;
> +	ioat = &zdev->kzdev->ioat;
> +	mutex_lock(&ioat->lock);
> +	idx = srcu_read_lock(&kvm->srcu);
> +	for (i = 0; i < ZPCI_TABLE_PAGES; i++) {
> +		page = gfn_to_page(kvm, gpa_to_gfn(gpa));
> +		if (is_error_page(page)) {
> +			srcu_read_unlock(&kvm->srcu, idx);
> +			rc = -EIO;
> +			goto out;

			goto unpin ?

> +		}
> +		iaddr = page_to_virt(page) + (gpa & ~PAGE_MASK);
> +		ioat->head[i] = (unsigned long *)iaddr;
> +		gpa += PAGE_SIZE;
> +	}
> +	srcu_read_unlock(&kvm->srcu, idx);
> +
> +	zdev->kzdev->ioat.seg = kcalloc(ZPCI_TABLE_ENTRIES_PAGES,
> +					sizeof(unsigned long *), GFP_KERNEL);

What about:

         ioat->seg = kcalloc(ZPCI_TABLE_ENTRIES_PAGES,
                             sizeof(*ioat->seg), GFP_KERNEL);
	if (!ioat->seg)
...
	ioat->pt = ...
?

> +	if (!zdev->kzdev->ioat.seg)
> +		goto unpin;
> +	zdev->kzdev->ioat.pt = kcalloc(ZPCI_TABLE_ENTRIES,
> +				       sizeof(unsigned long **), GFP_KERNEL);
> +	if (!zdev->kzdev->ioat.pt)
> +		goto free_seg;
> +
> +out:
> +	mutex_unlock(&ioat->lock);
> +	return rc;

	return 0 ?

> +
> +free_seg:
> +	kfree(zdev->kzdev->ioat.seg);

kfree(ioat->seg) ?
rc = -ENOMEM;

> +unpin:
> +	for (i = 0; i < ZPCI_TABLE_PAGES; i++) {
> +		kvm_release_pfn_dirty((u64)ioat->head[i] >> PAGE_SHIFT);
> +		ioat->head[i] = 0;
> +	}
> +	mutex_unlock(&ioat->lock);
> +	return -ENOMEM;

	return rc;

> +}
...snip...
Matthew Rosato Jan. 25, 2022, 2:47 p.m. UTC | #2 
On 1/25/22 8:29 AM, Pierre Morel wrote:
> 
> 
> On 1/14/22 21:31, Matthew Rosato wrote:
>> These routines will be wired into the vfio_pci_zdev ioctl handlers to
>> respond to requests to enable / disable a device for PCI I/O Address
>> Translation assistance.
>>
>> Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
>> ---
>>   arch/s390/include/asm/kvm_pci.h |  15 ++++
>>   arch/s390/include/asm/pci_dma.h |   2 +
>>   arch/s390/kvm/pci.c             | 139 ++++++++++++++++++++++++++++++++
>>   arch/s390/kvm/pci.h             |   2 +
>>   4 files changed, 158 insertions(+)
>>
>> diff --git a/arch/s390/include/asm/kvm_pci.h 
>> b/arch/s390/include/asm/kvm_pci.h
>> index 01fe14fffd7a..770849f13a70 100644
>> --- a/arch/s390/include/asm/kvm_pci.h
>> +++ b/arch/s390/include/asm/kvm_pci.h
>> @@ -16,11 +16,21 @@
>>   #include <linux/kvm_host.h>
>>   #include <linux/kvm.h>
>>   #include <linux/pci.h>
>> +#include <linux/mutex.h>
>>   #include <asm/pci_insn.h>
>> +#include <asm/pci_dma.h>
>> +
>> +struct kvm_zdev_ioat {
>> +    unsigned long *head[ZPCI_TABLE_PAGES];
>> +    unsigned long **seg;
>> +    unsigned long ***pt;
>> +    struct mutex lock;
> 
> Can we please rename the mutex ioat_lock to have a unique name easy to 
> follow for maintenance.
> Can you please add a description about when the lock should be used?
> 

OK.  The lock is meant to protect the contents of kvm_zdev_ioat -- I'll 
think of something to describe it.

>> +};
>>   struct kvm_zdev {
>>       struct zpci_dev *zdev;
>>       struct kvm *kvm;
>> +    struct kvm_zdev_ioat ioat;
>>       struct zpci_fib fib;
>>   };
>> @@ -33,6 +43,11 @@ int kvm_s390_pci_aif_enable(struct zpci_dev *zdev, 
>> struct zpci_fib *fib,
>>                   bool assist);
>>   int kvm_s390_pci_aif_disable(struct zpci_dev *zdev);
>> +int kvm_s390_pci_ioat_probe(struct zpci_dev *zdev);
>> +int kvm_s390_pci_ioat_enable(struct zpci_dev *zdev, u64 iota);
>> +int kvm_s390_pci_ioat_disable(struct zpci_dev *zdev);
>> +u8 kvm_s390_pci_get_dtsm(struct zpci_dev *zdev);
>> +
>>   int kvm_s390_pci_interp_probe(struct zpci_dev *zdev);
>>   int kvm_s390_pci_interp_enable(struct zpci_dev *zdev);
>>   int kvm_s390_pci_interp_disable(struct zpci_dev *zdev);
>> diff --git a/arch/s390/include/asm/pci_dma.h 
>> b/arch/s390/include/asm/pci_dma.h
>> index 91e63426bdc5..69e616d0712c 100644
>> --- a/arch/s390/include/asm/pci_dma.h
>> +++ b/arch/s390/include/asm/pci_dma.h
>> @@ -50,6 +50,8 @@ enum zpci_ioat_dtype {
>>   #define ZPCI_TABLE_ALIGN        ZPCI_TABLE_SIZE
>>   #define ZPCI_TABLE_ENTRY_SIZE        (sizeof(unsigned long))
>>   #define ZPCI_TABLE_ENTRIES        (ZPCI_TABLE_SIZE / 
>> ZPCI_TABLE_ENTRY_SIZE)
>> +#define ZPCI_TABLE_PAGES        (ZPCI_TABLE_SIZE >> PAGE_SHIFT)
>> +#define ZPCI_TABLE_ENTRIES_PAGES    (ZPCI_TABLE_ENTRIES * 
>> ZPCI_TABLE_PAGES)
>>   #define ZPCI_TABLE_BITS            11
>>   #define ZPCI_PT_BITS            8
>> diff --git a/arch/s390/kvm/pci.c b/arch/s390/kvm/pci.c
>> index 7ed9abc476b6..39c13c25a700 100644
>> --- a/arch/s390/kvm/pci.c
>> +++ b/arch/s390/kvm/pci.c
>> @@ -13,12 +13,15 @@
>>   #include <asm/pci.h>
>>   #include <asm/pci_insn.h>
>>   #include <asm/pci_io.h>
>> +#include <asm/pci_dma.h>
>>   #include <asm/sclp.h>
>>   #include "pci.h"
>>   #include "kvm-s390.h"
>>   struct zpci_aift *aift;
>> +#define shadow_ioat_init zdev->kzdev->ioat.head[0]
>> +
>>   static inline int __set_irq_noiib(u16 ctl, u8 isc)
>>   {
>>       union zpci_sic_iib iib = {{0}};
>> @@ -344,6 +347,135 @@ int kvm_s390_pci_aif_disable(struct zpci_dev *zdev)
>>   }
>>   EXPORT_SYMBOL_GPL(kvm_s390_pci_aif_disable);
>> +int kvm_s390_pci_ioat_probe(struct zpci_dev *zdev)
>> +{
>> +    /* Must have a KVM association registered */
> 
> may be add something like : "The ioat structure is embeded in kzdev"
> 
>> +    if (!zdev->kzdev || !zdev->kzdev->kvm)
> 
> Why do we need to check for kvm ?
> Having kzdev is already tested by the unique caller.
> 

We probably don't need to check for the kzdev because the caller already 
did this, agreed there.

But as for checking the kvm association, Alex asked for this in a 
comment to v1 (comment was against one of the vfio patches that call 
these routines) -- The reason being the probe comes from a userspace 
request and can be against any vfio-pci(-zdev) device at any time, and 
there's no point in proceeding if this device is not associated with a 
KVM guest -- It's possible for the KVM notifier to also pass a null KVM 
address -- so I think it's better to just be sure here.  In a 
well-behaved environment we would never see this (so, another case for 
an s390dbf entry)

>> +        return -EINVAL;
>> +
>> +    return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(kvm_s390_pci_ioat_probe);
>> +
>> +int kvm_s390_pci_ioat_enable(struct zpci_dev *zdev, u64 iota)
>> +{
>> +    gpa_t gpa = (gpa_t)(iota & ZPCI_RTE_ADDR_MASK);
>> +    struct kvm_zdev_ioat *ioat;
>> +    struct page *page;
>> +    struct kvm *kvm;
>> +    unsigned int idx;
>> +    void *iaddr;
>> +    int i, rc = 0;
> 
> no need to initialize rc

Agree based on the changes below

> 
>> +
>> +    if (shadow_ioat_init)
>> +        return -EINVAL;
>> +
>> +    /* Ensure supported type specified */
>> +    if ((iota & ZPCI_IOTA_RTTO_FLAG) != ZPCI_IOTA_RTTO_FLAG)
>> +        return -EINVAL;
>> +
>> +    kvm = zdev->kzdev->kvm;
>> +    ioat = &zdev->kzdev->ioat;
>> +    mutex_lock(&ioat->lock);
>> +    idx = srcu_read_lock(&kvm->srcu);
>> +    for (i = 0; i < ZPCI_TABLE_PAGES; i++) {
>> +        page = gfn_to_page(kvm, gpa_to_gfn(gpa));
>> +        if (is_error_page(page)) {
>> +            srcu_read_unlock(&kvm->srcu, idx);
>> +            rc = -EIO;
>> +            goto out;
> 
>              goto unpin ?

Ah, right, in case we hit this error somewhere in the middle of the loop.

> 
>> +        }
>> +        iaddr = page_to_virt(page) + (gpa & ~PAGE_MASK);
>> +        ioat->head[i] = (unsigned long *)iaddr;
>> +        gpa += PAGE_SIZE;
>> +    }
>> +    srcu_read_unlock(&kvm->srcu, idx);
>> +
>> +    zdev->kzdev->ioat.seg = kcalloc(ZPCI_TABLE_ENTRIES_PAGES,
>> +                    sizeof(unsigned long *), GFP_KERNEL);
> 
> What about:
> 
>          ioat->seg = kcalloc(ZPCI_TABLE_ENTRIES_PAGES,
>                              sizeof(*ioat->seg), GFP_KERNEL);
>      if (!ioat->seg)
> ...
>      ioat->pt = ...
> ?

Yep, would be fine (seems I forgot about the local *ioat here)

> 
>> +    if (!zdev->kzdev->ioat.seg)
>> +        goto unpin;
>> +    zdev->kzdev->ioat.pt = kcalloc(ZPCI_TABLE_ENTRIES,
>> +                       sizeof(unsigned long **), GFP_KERNEL);
>> +    if (!zdev->kzdev->ioat.pt)
>> +        goto free_seg;
>> +
>> +out:
>> +    mutex_unlock(&ioat->lock);
>> +    return rc;
> 
>      return 0 ?

Yes, we can do that now that we don't goto out: after is_error_page

> 
>> +
>> +free_seg:
>> +    kfree(zdev->kzdev->ioat.seg);
> 
> kfree(ioat->seg) ?
> rc = -ENOMEM;
> 
>> +unpin:
>> +    for (i = 0; i < ZPCI_TABLE_PAGES; i++) {
>> +        kvm_release_pfn_dirty((u64)ioat->head[i] >> PAGE_SHIFT);
>> +        ioat->head[i] = 0;
>> +    }
>> +    mutex_unlock(&ioat->lock);
>> +    return -ENOMEM;
> 
>      return rc;

And yes, agreed, now that we come here for other reasons (-EIO) we must 
return rc here and also set rc=-ENOMEM as you say for the kfree case above.
Pierre Morel Jan. 26, 2022, 8:30 a.m. UTC | #3 
On 1/25/22 15:47, Matthew Rosato wrote:
> On 1/25/22 8:29 AM, Pierre Morel wrote:
>>
>>
>> On 1/14/22 21:31, Matthew Rosato wrote:
>>> These routines will be wired into the vfio_pci_zdev ioctl handlers to
>>> respond to requests to enable / disable a device for PCI I/O Address
>>> Translation assistance.
>>>
>>> Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
>>> ---
>>>   arch/s390/include/asm/kvm_pci.h |  15 ++++
>>>   arch/s390/include/asm/pci_dma.h |   2 +
>>>   arch/s390/kvm/pci.c             | 139 ++++++++++++++++++++++++++++++++
>>>   arch/s390/kvm/pci.h             |   2 +
>>>   4 files changed, 158 insertions(+)
>>>
>>> diff --git a/arch/s390/include/asm/kvm_pci.h 
>>> b/arch/s390/include/asm/kvm_pci.h
>>> index 01fe14fffd7a..770849f13a70 100644
>>> --- a/arch/s390/include/asm/kvm_pci.h
>>> +++ b/arch/s390/include/asm/kvm_pci.h
>>> @@ -16,11 +16,21 @@
>>>   #include <linux/kvm_host.h>
>>>   #include <linux/kvm.h>
>>>   #include <linux/pci.h>
>>> +#include <linux/mutex.h>
>>>   #include <asm/pci_insn.h>
>>> +#include <asm/pci_dma.h>
>>> +
>>> +struct kvm_zdev_ioat {
>>> +    unsigned long *head[ZPCI_TABLE_PAGES];
>>> +    unsigned long **seg;
>>> +    unsigned long ***pt;
>>> +    struct mutex lock;
>>
>> Can we please rename the mutex ioat_lock to have a unique name easy to 
>> follow for maintenance.
>> Can you please add a description about when the lock should be used?
>>
> 
> OK.  The lock is meant to protect the contents of kvm_zdev_ioat -- I'll 
> think of something to describe it.
> 
>>> +};
>>>   struct kvm_zdev {
>>>       struct zpci_dev *zdev;
>>>       struct kvm *kvm;
>>> +    struct kvm_zdev_ioat ioat;
>>>       struct zpci_fib fib;
>>>   };
>>> @@ -33,6 +43,11 @@ int kvm_s390_pci_aif_enable(struct zpci_dev *zdev, 
>>> struct zpci_fib *fib,
>>>                   bool assist);
>>>   int kvm_s390_pci_aif_disable(struct zpci_dev *zdev);
>>> +int kvm_s390_pci_ioat_probe(struct zpci_dev *zdev);
>>> +int kvm_s390_pci_ioat_enable(struct zpci_dev *zdev, u64 iota);
>>> +int kvm_s390_pci_ioat_disable(struct zpci_dev *zdev);
>>> +u8 kvm_s390_pci_get_dtsm(struct zpci_dev *zdev);
>>> +
>>>   int kvm_s390_pci_interp_probe(struct zpci_dev *zdev);
>>>   int kvm_s390_pci_interp_enable(struct zpci_dev *zdev);
>>>   int kvm_s390_pci_interp_disable(struct zpci_dev *zdev);
>>> diff --git a/arch/s390/include/asm/pci_dma.h 
>>> b/arch/s390/include/asm/pci_dma.h
>>> index 91e63426bdc5..69e616d0712c 100644
>>> --- a/arch/s390/include/asm/pci_dma.h
>>> +++ b/arch/s390/include/asm/pci_dma.h
>>> @@ -50,6 +50,8 @@ enum zpci_ioat_dtype {
>>>   #define ZPCI_TABLE_ALIGN        ZPCI_TABLE_SIZE
>>>   #define ZPCI_TABLE_ENTRY_SIZE        (sizeof(unsigned long))
>>>   #define ZPCI_TABLE_ENTRIES        (ZPCI_TABLE_SIZE / 
>>> ZPCI_TABLE_ENTRY_SIZE)
>>> +#define ZPCI_TABLE_PAGES        (ZPCI_TABLE_SIZE >> PAGE_SHIFT)
>>> +#define ZPCI_TABLE_ENTRIES_PAGES    (ZPCI_TABLE_ENTRIES * 
>>> ZPCI_TABLE_PAGES)
>>>   #define ZPCI_TABLE_BITS            11
>>>   #define ZPCI_PT_BITS            8
>>> diff --git a/arch/s390/kvm/pci.c b/arch/s390/kvm/pci.c
>>> index 7ed9abc476b6..39c13c25a700 100644
>>> --- a/arch/s390/kvm/pci.c
>>> +++ b/arch/s390/kvm/pci.c
>>> @@ -13,12 +13,15 @@
>>>   #include <asm/pci.h>
>>>   #include <asm/pci_insn.h>
>>>   #include <asm/pci_io.h>
>>> +#include <asm/pci_dma.h>
>>>   #include <asm/sclp.h>
>>>   #include "pci.h"
>>>   #include "kvm-s390.h"
>>>   struct zpci_aift *aift;
>>> +#define shadow_ioat_init zdev->kzdev->ioat.head[0]
>>> +
>>>   static inline int __set_irq_noiib(u16 ctl, u8 isc)
>>>   {
>>>       union zpci_sic_iib iib = {{0}};
>>> @@ -344,6 +347,135 @@ int kvm_s390_pci_aif_disable(struct zpci_dev 
>>> *zdev)
>>>   }
>>>   EXPORT_SYMBOL_GPL(kvm_s390_pci_aif_disable);
>>> +int kvm_s390_pci_ioat_probe(struct zpci_dev *zdev)
>>> +{
>>> +    /* Must have a KVM association registered */
>>
>> may be add something like : "The ioat structure is embeded in kzdev"
>>
>>> +    if (!zdev->kzdev || !zdev->kzdev->kvm)
>>
>> Why do we need to check for kvm ?
>> Having kzdev is already tested by the unique caller.
>>
> 
> We probably don't need to check for the kzdev because the caller already 
> did this, agreed there.
> 
> But as for checking the kvm association, Alex asked for this in a 
> comment to v1 (comment was against one of the vfio patches that call 
> these routines) -- The reason being the probe comes from a userspace 
> request and can be against any vfio-pci(-zdev) device at any time, and 
> there's no point in proceeding if this device is not associated with a 
> KVM guest -- It's possible for the KVM notifier to also pass a null KVM 
> address -- so I think it's better to just be sure here.  In a 
> well-behaved environment we would never see this (so, another case for 
> an s390dbf entry)

I thought the check could be done even if the userspace is not 
associated with KVM. But of course OK if Alex asked I would have missed 
some point.
diff mbox series

Patch

diff --git a/arch/s390/include/asm/kvm_pci.h b/arch/s390/include/asm/kvm_pci.h
index 01fe14fffd7a..770849f13a70 100644
--- a/arch/s390/include/asm/kvm_pci.h
+++ b/arch/s390/include/asm/kvm_pci.h
@@ -16,11 +16,21 @@ 
 #include <linux/kvm_host.h>
 #include <linux/kvm.h>
 #include <linux/pci.h>
+#include <linux/mutex.h>
 #include <asm/pci_insn.h>
+#include <asm/pci_dma.h>
+
+struct kvm_zdev_ioat {
+	unsigned long *head[ZPCI_TABLE_PAGES];
+	unsigned long **seg;
+	unsigned long ***pt;
+	struct mutex lock;
+};
 
 struct kvm_zdev {
 	struct zpci_dev *zdev;
 	struct kvm *kvm;
+	struct kvm_zdev_ioat ioat;
 	struct zpci_fib fib;
 };
 
@@ -33,6 +43,11 @@  int kvm_s390_pci_aif_enable(struct zpci_dev *zdev, struct zpci_fib *fib,
 			    bool assist);
 int kvm_s390_pci_aif_disable(struct zpci_dev *zdev);
 
+int kvm_s390_pci_ioat_probe(struct zpci_dev *zdev);
+int kvm_s390_pci_ioat_enable(struct zpci_dev *zdev, u64 iota);
+int kvm_s390_pci_ioat_disable(struct zpci_dev *zdev);
+u8 kvm_s390_pci_get_dtsm(struct zpci_dev *zdev);
+
 int kvm_s390_pci_interp_probe(struct zpci_dev *zdev);
 int kvm_s390_pci_interp_enable(struct zpci_dev *zdev);
 int kvm_s390_pci_interp_disable(struct zpci_dev *zdev);
diff --git a/arch/s390/include/asm/pci_dma.h b/arch/s390/include/asm/pci_dma.h
index 91e63426bdc5..69e616d0712c 100644
--- a/arch/s390/include/asm/pci_dma.h
+++ b/arch/s390/include/asm/pci_dma.h
@@ -50,6 +50,8 @@  enum zpci_ioat_dtype {
 #define ZPCI_TABLE_ALIGN		ZPCI_TABLE_SIZE
 #define ZPCI_TABLE_ENTRY_SIZE		(sizeof(unsigned long))
 #define ZPCI_TABLE_ENTRIES		(ZPCI_TABLE_SIZE / ZPCI_TABLE_ENTRY_SIZE)
+#define ZPCI_TABLE_PAGES		(ZPCI_TABLE_SIZE >> PAGE_SHIFT)
+#define ZPCI_TABLE_ENTRIES_PAGES	(ZPCI_TABLE_ENTRIES * ZPCI_TABLE_PAGES)
 
 #define ZPCI_TABLE_BITS			11
 #define ZPCI_PT_BITS			8
diff --git a/arch/s390/kvm/pci.c b/arch/s390/kvm/pci.c
index 7ed9abc476b6..39c13c25a700 100644
--- a/arch/s390/kvm/pci.c
+++ b/arch/s390/kvm/pci.c
@@ -13,12 +13,15 @@ 
 #include <asm/pci.h>
 #include <asm/pci_insn.h>
 #include <asm/pci_io.h>
+#include <asm/pci_dma.h>
 #include <asm/sclp.h>
 #include "pci.h"
 #include "kvm-s390.h"
 
 struct zpci_aift *aift;
 
+#define shadow_ioat_init zdev->kzdev->ioat.head[0]
+
 static inline int __set_irq_noiib(u16 ctl, u8 isc)
 {
 	union zpci_sic_iib iib = {{0}};
@@ -344,6 +347,135 @@  int kvm_s390_pci_aif_disable(struct zpci_dev *zdev)
 }
 EXPORT_SYMBOL_GPL(kvm_s390_pci_aif_disable);
 
+int kvm_s390_pci_ioat_probe(struct zpci_dev *zdev)
+{
+	/* Must have a KVM association registered */
+	if (!zdev->kzdev || !zdev->kzdev->kvm)
+		return -EINVAL;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(kvm_s390_pci_ioat_probe);
+
+int kvm_s390_pci_ioat_enable(struct zpci_dev *zdev, u64 iota)
+{
+	gpa_t gpa = (gpa_t)(iota & ZPCI_RTE_ADDR_MASK);
+	struct kvm_zdev_ioat *ioat;
+	struct page *page;
+	struct kvm *kvm;
+	unsigned int idx;
+	void *iaddr;
+	int i, rc = 0;
+
+	if (shadow_ioat_init)
+		return -EINVAL;
+
+	/* Ensure supported type specified */
+	if ((iota & ZPCI_IOTA_RTTO_FLAG) != ZPCI_IOTA_RTTO_FLAG)
+		return -EINVAL;
+
+	kvm = zdev->kzdev->kvm;
+	ioat = &zdev->kzdev->ioat;
+	mutex_lock(&ioat->lock);
+	idx = srcu_read_lock(&kvm->srcu);
+	for (i = 0; i < ZPCI_TABLE_PAGES; i++) {
+		page = gfn_to_page(kvm, gpa_to_gfn(gpa));
+		if (is_error_page(page)) {
+			srcu_read_unlock(&kvm->srcu, idx);
+			rc = -EIO;
+			goto out;
+		}
+		iaddr = page_to_virt(page) + (gpa & ~PAGE_MASK);
+		ioat->head[i] = (unsigned long *)iaddr;
+		gpa += PAGE_SIZE;
+	}
+	srcu_read_unlock(&kvm->srcu, idx);
+
+	zdev->kzdev->ioat.seg = kcalloc(ZPCI_TABLE_ENTRIES_PAGES,
+					sizeof(unsigned long *), GFP_KERNEL);
+	if (!zdev->kzdev->ioat.seg)
+		goto unpin;
+	zdev->kzdev->ioat.pt = kcalloc(ZPCI_TABLE_ENTRIES,
+				       sizeof(unsigned long **), GFP_KERNEL);
+	if (!zdev->kzdev->ioat.pt)
+		goto free_seg;
+
+out:
+	mutex_unlock(&ioat->lock);
+	return rc;
+
+free_seg:
+	kfree(zdev->kzdev->ioat.seg);
+unpin:
+	for (i = 0; i < ZPCI_TABLE_PAGES; i++) {
+		kvm_release_pfn_dirty((u64)ioat->head[i] >> PAGE_SHIFT);
+		ioat->head[i] = 0;
+	}
+	mutex_unlock(&ioat->lock);
+	return -ENOMEM;
+}
+EXPORT_SYMBOL_GPL(kvm_s390_pci_ioat_enable);
+
+static void free_pt_entry(struct kvm_zdev_ioat *ioat, int st, int pt)
+{
+	if (!ioat->pt[st][pt])
+		return;
+
+	kvm_release_pfn_dirty((u64)ioat->pt[st][pt]);
+}
+
+static void free_seg_entry(struct kvm_zdev_ioat *ioat, int entry)
+{
+	int i, st, count = 0;
+
+	for (i = 0; i < ZPCI_TABLE_PAGES; i++) {
+		if (ioat->seg[entry + i]) {
+			kvm_release_pfn_dirty((u64)ioat->seg[entry + i]);
+			count++;
+		}
+	}
+
+	if (count == 0)
+		return;
+
+	st = entry / ZPCI_TABLE_PAGES;
+	for (i = 0; i < ZPCI_TABLE_ENTRIES; i++)
+		free_pt_entry(ioat, st, i);
+	kfree(ioat->pt[st]);
+}
+
+int kvm_s390_pci_ioat_disable(struct zpci_dev *zdev)
+{
+	struct kvm_zdev_ioat *ioat;
+	int i;
+
+	if (!shadow_ioat_init)
+		return -EINVAL;
+
+	ioat = &zdev->kzdev->ioat;
+	mutex_lock(&ioat->lock);
+	for (i = 0; i < ZPCI_TABLE_PAGES; i++) {
+		kvm_release_pfn_dirty((u64)ioat->head[i] >> PAGE_SHIFT);
+		ioat->head[i] = 0;
+	}
+
+	for (i = 0; i < ZPCI_TABLE_ENTRIES_PAGES; i += ZPCI_TABLE_PAGES)
+		free_seg_entry(ioat, i);
+
+	kfree(ioat->seg);
+	kfree(ioat->pt);
+	mutex_unlock(&ioat->lock);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(kvm_s390_pci_ioat_disable);
+
+u8 kvm_s390_pci_get_dtsm(struct zpci_dev *zdev)
+{
+	return (zdev->dtsm & KVM_S390_PCI_DTSM_MASK);
+}
+EXPORT_SYMBOL_GPL(kvm_s390_pci_get_dtsm);
+
 int kvm_s390_pci_interp_probe(struct zpci_dev *zdev)
 {
 	/* Must have appropriate hardware facilities */
@@ -424,6 +556,10 @@  int kvm_s390_pci_interp_disable(struct zpci_dev *zdev)
 	if (zdev->kzdev->fib.fmt0.aibv != 0)
 		kvm_s390_pci_aif_disable(zdev);
 
+	/* If we are using the IOAT assist, disable it now */
+	if (zdev->kzdev->ioat.head[0])
+		kvm_s390_pci_ioat_disable(zdev);
+
 	/* Remove the host CLP guest designation */
 	zdev->gd = 0;
 
@@ -453,6 +589,8 @@  int kvm_s390_pci_dev_open(struct zpci_dev *zdev)
 	if (!kzdev)
 		return -ENOMEM;
 
+	mutex_init(&kzdev->ioat.lock);
+
 	kzdev->zdev = zdev;
 	zdev->kzdev = kzdev;
 
@@ -467,6 +605,7 @@  void kvm_s390_pci_dev_release(struct zpci_dev *zdev)
 	kzdev = zdev->kzdev;
 	WARN_ON(kzdev->zdev != zdev);
 	zdev->kzdev = 0;
+	mutex_destroy(&kzdev->ioat.lock);
 	kfree(kzdev);
 }
 EXPORT_SYMBOL_GPL(kvm_s390_pci_dev_release);
diff --git a/arch/s390/kvm/pci.h b/arch/s390/kvm/pci.h
index 387b637863c9..54355634df82 100644
--- a/arch/s390/kvm/pci.h
+++ b/arch/s390/kvm/pci.h
@@ -16,6 +16,8 @@ 
 #include <asm/airq.h>
 #include <asm/kvm_pci.h>
 
+#define KVM_S390_PCI_DTSM_MASK 0x40
+
 struct zpci_gaite {
 	u32 gisa;
 	u8 gisc;