Messages in this thread | ![/](/images/icornerl.gif) | | Date | Tue, 14 Dec 2021 13:13:11 -0500 | Subject | Re: [PATCH 22/32] KVM: s390: pci: provide routines for enabling/disabling IOAT assist | From | Matthew Rosato <> |
| |
On 12/14/21 12:46 PM, Pierre Morel wrote: > > > On 12/7/21 21:57, 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 | 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; > > The only caller already checked zdev->kzdev.
I tend to get overzealous with these checks..
> Could we use a macro to replace zdev->kzdev->ioat.head[0] ? > like > #define shadow_pgtbl_initialized zdev->kzdev->ioat.head[0] > > Would be clearer for me.
Sure
> >> + >> + /* 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));
In relation to your question below about where things are being pinned...
Here the call to gfn_to_page does the pin (this call eventually drives hva_to_pfn for pinning)
>> + 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;
^^ here we store what was pinned above in ioat->head[] and can use it later for unpinning.
But looking again now I think for the is_error_page() case above here I should also be going to unpin: to cleanup in case we were somewhere in the middle of the loop and so have some pages pinned already.
>> + 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); > > I did not find when the pages are pinned.
See above.
> >> + ioat->head[i] = 0; >> + } >> + mutex_unlock(&ioat->lock); >> + return -ENOMEM; >> +} >> +EXPORT_SYMBOL_GPL(kvm_s390_pci_ioat_enable); >> + > > ...snip... >> >
| ![\](/images/icornerr.gif) |