[PATCH 22/32] KVM: s390: pci: provide routines for enabling/disabling IOAT assist

Matthew Rosato
2021-12-07T21:00:18Z

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 | 133 ++++++++++++++++++++++++++++++++
arch/s390/kvm/pci.h | 2 +
4 files changed, 152 insertions(+)

diff --git a/arch/s390/include/asm/kvm_pci.h b/arch/s390/include/asm/kvm_pci.h
index 54a0afdbe7d0..254275399f21 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 @@ extern int kvm_s390_pci_aif_enable(struct zpci_dev *zdev, struct zpci_fib *fib,
bool assist);
extern int kvm_s390_pci_aif_disable(struct zpci_dev *zdev);

+extern int kvm_s390_pci_ioat_probe(struct zpci_dev *zdev);
+extern int kvm_s390_pci_ioat_enable(struct zpci_dev *zdev, u64 iota);
+extern int kvm_s390_pci_ioat_disable(struct zpci_dev *zdev);
+extern u8 kvm_s390_pci_get_dtsm(struct zpci_dev *zdev);
+
extern int kvm_s390_pci_interp_probe(struct zpci_dev *zdev);
extern int kvm_s390_pci_interp_enable(struct zpci_dev *zdev);
extern 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 3b8e89d4578a..e1d3c1d3fc8a 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 3a29398dd53b..a1c0c0881332 100644
--- a/arch/s390/kvm/pci.c
+++ b/arch/s390/kvm/pci.c
@@ -12,6 +12,7 @@
#include <asm/kvm_pci.h>
#include <asm/pci.h>
#include <asm/pci_insn.h>
+#include <asm/pci_dma.h>
#include <asm/sclp.h>
#include "pci.h"
#include "kvm-s390.h"
@@ -315,6 +316,131 @@ 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)
+{
+ 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 (!zdev->kzdev || !zdev->kzdev->kvm || zdev->kzdev->ioat.head[0])
+ 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 (!zdev->kzdev || !zdev->kzdev->kvm || !zdev->kzdev->ioat.head[0])
+ 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)
{
if (!(sclp.has_zpci_interp && test_facility(69)))
@@ -387,6 +513,10 @@ 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;

@@ -419,6 +549,8 @@ 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;

@@ -436,6 +568,7 @@ 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);

}
diff --git a/arch/s390/kvm/pci.h b/arch/s390/kvm/pci.h
index 776b2745c675..3c86888fe1b3 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 {
unsigned int gisa;
u8 gisc;
--
2.27.0