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Message-ID: <107d60a4-e31f-5bfa-fc1c-8340b8bbf573@linux.ibm.com>
Date: Mon, 14 Feb 2022 14:22:50 +0100
From: Pierre Morel <pmorel@...ux.ibm.com>
To: Matthew Rosato <mjrosato@...ux.ibm.com>, linux-s390@...r.kernel.org
Cc: alex.williamson@...hat.com, cohuck@...hat.com,
schnelle@...ux.ibm.com, farman@...ux.ibm.com,
borntraeger@...ux.ibm.com, hca@...ux.ibm.com, gor@...ux.ibm.com,
gerald.schaefer@...ux.ibm.com, agordeev@...ux.ibm.com,
frankja@...ux.ibm.com, david@...hat.com, imbrenda@...ux.ibm.com,
vneethv@...ux.ibm.com, oberpar@...ux.ibm.com, freude@...ux.ibm.com,
thuth@...hat.com, pasic@...ux.ibm.com, kvm@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 19/30] KVM: s390: pci: provide routines for
enabling/disabling interpretation
On 2/4/22 22:15, 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 zPCI Load/Store
> interpretation.
>
> The first time such a request is received, enable the necessary facilities
> for the guest.
>
> Signed-off-by: Matthew Rosato <mjrosato@...ux.ibm.com>
> ---
> arch/s390/include/asm/kvm_pci.h | 4 ++
> arch/s390/kvm/pci.c | 102 ++++++++++++++++++++++++++++++++
> arch/s390/pci/pci.c | 3 +
> 3 files changed, 109 insertions(+)
>
> diff --git a/arch/s390/include/asm/kvm_pci.h b/arch/s390/include/asm/kvm_pci.h
> index ef10f9e46e37..422701d526dd 100644
> --- a/arch/s390/include/asm/kvm_pci.h
> +++ b/arch/s390/include/asm/kvm_pci.h
> @@ -24,4 +24,8 @@ struct kvm_zdev {
> int kvm_s390_pci_dev_open(struct zpci_dev *zdev);
> void kvm_s390_pci_dev_release(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);
> +
> #endif /* ASM_KVM_PCI_H */
> diff --git a/arch/s390/kvm/pci.c b/arch/s390/kvm/pci.c
> index 9b8390133e15..16bef3935284 100644
> --- a/arch/s390/kvm/pci.c
> +++ b/arch/s390/kvm/pci.c
> @@ -12,7 +12,9 @@
> #include <asm/kvm_pci.h>
> #include <asm/pci.h>
> #include <asm/pci_insn.h>
> +#include <asm/sclp.h>
> #include "pci.h"
> +#include "kvm-s390.h"
>
> struct zpci_aift *aift;
>
> @@ -153,6 +155,106 @@ int kvm_s390_pci_aen_init(u8 nisc)
> return rc;
> }
>
> +int kvm_s390_pci_interp_probe(struct zpci_dev *zdev)
> +{
> + /* Must have appropriate hardware facilities */
> + if (!sclp.has_zpci_lsi || !sclp.has_aisii || !sclp.has_aeni ||
> + !sclp.has_aisi || !test_facility(69) || !test_facility(70) ||
> + !test_facility(71) || !test_facility(72)) {
> + return -EINVAL;
> + }
I do not think we need to check STFLE facilities when the SCLP bit
indicating the interpretation of a facility is installed the STFLE bit
indicating the interpreted facility is also installed.
Otherwise, look good to me, with this change:
Reviewed-by: Pierre Morel <pmorel@...ux.ibm.com>
> +
> + /* Must have a KVM association registered */
> + if (!zdev->kzdev || !zdev->kzdev->kvm)
> + return -EINVAL;
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(kvm_s390_pci_interp_probe);
> +
> +int kvm_s390_pci_interp_enable(struct zpci_dev *zdev)
> +{
> + u32 gisa;
> + int rc;
> +
> + if (!zdev->kzdev || !zdev->kzdev->kvm)
> + return -EINVAL;
> +
> + /*
> + * If this is the first request to use an interpreted device, make the
> + * necessary vcpu changes
> + */
> + if (!zdev->kzdev->kvm->arch.use_zpci_interp)
> + kvm_s390_vcpu_pci_enable_interp(zdev->kzdev->kvm);
> +
> + /*
> + * In the event of a system reset in userspace, the GISA designation
> + * may still be assigned because the device is still enabled.
> + * Verify it's the same guest before proceeding.
> + */
> + gisa = (u32)virt_to_phys(&zdev->kzdev->kvm->arch.sie_page2->gisa);
> + if (zdev->gisa != 0 && zdev->gisa != gisa)
> + return -EPERM;
> +
> + if (zdev_enabled(zdev)) {
> + zdev->gisa = 0;
> + rc = zpci_disable_device(zdev);
> + if (rc)
> + return rc;
> + }
> +
> + /*
> + * Store information about the identity of the kvm guest allowed to
> + * access this device via interpretation to be used by host CLP
> + */
> + zdev->gisa = gisa;
> +
> + rc = zpci_enable_device(zdev);
> + if (rc)
> + goto err;
> +
> + /* Re-register the IOMMU that was already created */
> + rc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
> + virt_to_phys(zdev->dma_table));
> + if (rc)
> + goto err;
> +
> + return rc;
> +
> +err:
> + zdev->gisa = 0;
> + return rc;
> +}
> +EXPORT_SYMBOL_GPL(kvm_s390_pci_interp_enable);
> +
> +int kvm_s390_pci_interp_disable(struct zpci_dev *zdev)
> +{
> + int rc;
> +
> + if (zdev->gisa == 0)
> + return -EINVAL;
> +
> + /* Remove the host CLP guest designation */
> + zdev->gisa = 0;
> +
> + if (zdev_enabled(zdev)) {
> + rc = zpci_disable_device(zdev);
> + if (rc)
> + return rc;
> + }
> +
> + rc = zpci_enable_device(zdev);
> + if (rc)
> + return rc;
> +
> + /* Re-register the IOMMU that was already created */
> + rc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
> + virt_to_phys(zdev->dma_table));
> +
> + return rc;
> +}
> +EXPORT_SYMBOL_GPL(kvm_s390_pci_interp_disable);
> +
> int kvm_s390_pci_dev_open(struct zpci_dev *zdev)
> {
> struct kvm_zdev *kzdev;
> diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c
> index 13033717cd4e..5dbe49ec325e 100644
> --- a/arch/s390/pci/pci.c
> +++ b/arch/s390/pci/pci.c
> @@ -147,6 +147,7 @@ int zpci_register_ioat(struct zpci_dev *zdev, u8 dmaas,
> zpci_dbg(3, "reg ioat fid:%x, cc:%d, status:%d\n", zdev->fid, cc, status);
> return cc;
> }
> +EXPORT_SYMBOL_GPL(zpci_register_ioat);
>
> /* Modify PCI: Unregister I/O address translation parameters */
> int zpci_unregister_ioat(struct zpci_dev *zdev, u8 dmaas)
> @@ -727,6 +728,7 @@ int zpci_enable_device(struct zpci_dev *zdev)
> zpci_update_fh(zdev, fh);
> return rc;
> }
> +EXPORT_SYMBOL_GPL(zpci_enable_device);
>
> int zpci_disable_device(struct zpci_dev *zdev)
> {
> @@ -750,6 +752,7 @@ int zpci_disable_device(struct zpci_dev *zdev)
> }
> return rc;
> }
> +EXPORT_SYMBOL_GPL(zpci_disable_device);
>
> /**
> * zpci_hot_reset_device - perform a reset of the given zPCI function
>
--
Pierre Morel
IBM Lab Boeblingen
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