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 <[email protected]>
---
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;
+};
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;
--
2.27.0
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 <[email protected]>
> ---
> 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...
--
Pierre Morel
IBM Lab Boeblingen
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 <[email protected]>
>> ---
>> 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.
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 <[email protected]>
>>> ---
>>> 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.
--
Pierre Morel
IBM Lab Boeblingen