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

From: Matthew Rosato
Date: Fri Jan 14 2022 - 15:33:47 EST

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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@xxxxxxxxxxxxx>
---
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

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