These routines will be invoked at the time an s390x vfio-pci device is
associated with a KVM (or when the association is removed), allowing
the zPCI device to enable or disable load/store intepretation mode;
this requires the host zPCI device to inform firmware of the unique
token (GISA designation) that is associated with the owning KVM.
Signed-off-by: Matthew Rosato <[email protected]>
---
arch/s390/include/asm/kvm_host.h | 18 ++++
arch/s390/include/asm/pci.h | 1 +
arch/s390/kvm/kvm-s390.c | 15 +++
arch/s390/kvm/pci.c | 162 +++++++++++++++++++++++++++++++
arch/s390/kvm/pci.h | 5 +
arch/s390/pci/pci.c | 4 +
6 files changed, 205 insertions(+)
diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index 8e381603b6a7..6e83d746bae2 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -19,6 +19,7 @@
#include <linux/kvm.h>
#include <linux/seqlock.h>
#include <linux/module.h>
+#include <linux/pci.h>
#include <asm/debug.h>
#include <asm/cpu.h>
#include <asm/fpu/api.h>
@@ -967,6 +968,8 @@ struct kvm_arch{
DECLARE_BITMAP(idle_mask, KVM_MAX_VCPUS);
struct kvm_s390_gisa_interrupt gisa_int;
struct kvm_s390_pv pv;
+ struct list_head kzdev_list;
+ spinlock_t kzdev_list_lock;
};
#define KVM_HVA_ERR_BAD (-1UL)
@@ -1017,4 +1020,19 @@ static inline void kvm_arch_flush_shadow_memslot(struct kvm *kvm,
static inline void kvm_arch_vcpu_blocking(struct kvm_vcpu *vcpu) {}
static inline void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu) {}
+#define __KVM_HAVE_ARCH_VM_FREE
+void kvm_arch_free_vm(struct kvm *kvm);
+
+#ifdef CONFIG_VFIO_PCI_ZDEV_KVM
+int kvm_s390_pci_register_kvm(struct zpci_dev *zdev, struct kvm *kvm);
+void kvm_s390_pci_unregister_kvm(struct zpci_dev *zdev);
+#else
+static inline int kvm_s390_pci_register_kvm(struct zpci_dev *dev,
+ struct kvm *kvm)
+{
+ return -EPERM;
+}
+static inline void kvm_s390_pci_unregister_kvm(struct zpci_dev *dev) {}
+#endif
+
#endif
diff --git a/arch/s390/include/asm/pci.h b/arch/s390/include/asm/pci.h
index 322060a75d9f..85eb0ef9d4c3 100644
--- a/arch/s390/include/asm/pci.h
+++ b/arch/s390/include/asm/pci.h
@@ -194,6 +194,7 @@ struct zpci_dev {
/* IOMMU and passthrough */
struct s390_domain *s390_domain; /* s390 IOMMU domain data */
struct kvm_zdev *kzdev;
+ struct mutex kzdev_lock;
};
static inline bool zdev_enabled(struct zpci_dev *zdev)
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index a66da3f66114..4758bb731199 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -2790,6 +2790,14 @@ static void sca_dispose(struct kvm *kvm)
kvm->arch.sca = NULL;
}
+void kvm_arch_free_vm(struct kvm *kvm)
+{
+ if (IS_ENABLED(CONFIG_VFIO_PCI_ZDEV_KVM))
+ kvm_s390_pci_clear_list(kvm);
+
+ __kvm_arch_free_vm(kvm);
+}
+
int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
{
gfp_t alloc_flags = GFP_KERNEL_ACCOUNT;
@@ -2872,6 +2880,13 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
kvm_s390_crypto_init(kvm);
+ if (IS_ENABLED(CONFIG_VFIO_PCI_ZDEV_KVM)) {
+ mutex_lock(&kvm->lock);
+ kvm_s390_pci_init_list(kvm);
+ kvm_s390_vcpu_pci_enable_interp(kvm);
+ mutex_unlock(&kvm->lock);
+ }
+
mutex_init(&kvm->arch.float_int.ais_lock);
spin_lock_init(&kvm->arch.float_int.lock);
for (i = 0; i < FIRQ_LIST_COUNT; i++)
diff --git a/arch/s390/kvm/pci.c b/arch/s390/kvm/pci.c
index b232c8cbaa81..24211741deb0 100644
--- a/arch/s390/kvm/pci.c
+++ b/arch/s390/kvm/pci.c
@@ -12,7 +12,9 @@
#include <asm/pci.h>
#include <asm/pci_insn.h>
#include <asm/pci_io.h>
+#include <asm/sclp.h>
#include "pci.h"
+#include "kvm-s390.h"
struct zpci_aift *aift;
@@ -423,6 +425,166 @@ static void kvm_s390_pci_dev_release(struct zpci_dev *zdev)
kfree(kzdev);
}
+
+/*
+ * Register device with the specified KVM. If interpetation facilities are
+ * available, enable them and let userspace indicate whether or not they will
+ * be used (specify SHM bit to disable).
+ */
+int kvm_s390_pci_register_kvm(struct zpci_dev *zdev, struct kvm *kvm)
+{
+ int rc;
+
+ if (!zdev)
+ return -EINVAL;
+
+ mutex_lock(&zdev->kzdev_lock);
+
+ if (zdev->kzdev || zdev->gisa != 0 || !kvm) {
+ mutex_unlock(&zdev->kzdev_lock);
+ return -EINVAL;
+ }
+
+ kvm_get_kvm(kvm);
+
+ mutex_lock(&kvm->lock);
+
+ rc = kvm_s390_pci_dev_open(zdev);
+ if (rc)
+ goto err;
+
+ /*
+ * If interpretation facilities aren't available, add the device to
+ * the kzdev list but don't enable for interpretation.
+ */
+ if (!kvm_s390_pci_interp_allowed())
+ goto out;
+
+ /*
+ * If this is the first request to use an interpreted device, make the
+ * necessary vcpu changes
+ */
+ if (!kvm->arch.use_zpci_interp)
+ kvm_s390_vcpu_pci_enable_interp(kvm);
+
+ if (zdev_enabled(zdev)) {
+ rc = zpci_disable_device(zdev);
+ if (rc)
+ goto err;
+ }
+
+ /*
+ * Store information about the identity of the kvm guest allowed to
+ * access this device via interpretation to be used by host CLP
+ */
+ zdev->gisa = (u32)virt_to_phys(&kvm->arch.sie_page2->gisa);
+
+ rc = zpci_enable_device(zdev);
+ if (rc)
+ goto clear_gisa;
+
+ /* 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 clear_gisa;
+
+out:
+ zdev->kzdev->kvm = kvm;
+
+ spin_lock(&kvm->arch.kzdev_list_lock);
+ list_add_tail(&zdev->kzdev->entry, &kvm->arch.kzdev_list);
+ spin_unlock(&kvm->arch.kzdev_list_lock);
+
+ mutex_unlock(&kvm->lock);
+ mutex_unlock(&zdev->kzdev_lock);
+ return 0;
+
+clear_gisa:
+ zdev->gisa = 0;
+err:
+ if (zdev->kzdev)
+ kvm_s390_pci_dev_release(zdev);
+ mutex_unlock(&kvm->lock);
+ mutex_unlock(&zdev->kzdev_lock);
+ kvm_put_kvm(kvm);
+ return rc;
+}
+EXPORT_SYMBOL_GPL(kvm_s390_pci_register_kvm);
+
+void kvm_s390_pci_unregister_kvm(struct zpci_dev *zdev)
+{
+ struct kvm *kvm;
+
+ if (!zdev)
+ return;
+
+ mutex_lock(&zdev->kzdev_lock);
+
+ if (WARN_ON(!zdev->kzdev)) {
+ mutex_unlock(&zdev->kzdev_lock);
+ return;
+ }
+
+ kvm = zdev->kzdev->kvm;
+ mutex_lock(&kvm->lock);
+
+ /*
+ * A 0 gisa means interpretation was never enabled, just remove the
+ * device from the list.
+ */
+ if (zdev->gisa == 0)
+ goto out;
+
+ /* Forwarding must be turned off before interpretation */
+ if (zdev->kzdev->fib.fmt0.aibv != 0)
+ kvm_s390_pci_aif_disable(zdev, true);
+
+ /* Remove the host CLP guest designation */
+ zdev->gisa = 0;
+
+ if (zdev_enabled(zdev)) {
+ if (zpci_disable_device(zdev))
+ goto out;
+ }
+
+ if (zpci_enable_device(zdev))
+ goto out;
+
+ /* Re-register the IOMMU that was already created */
+ zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
+ virt_to_phys(zdev->dma_table));
+
+out:
+ spin_lock(&kvm->arch.kzdev_list_lock);
+ list_del(&zdev->kzdev->entry);
+ spin_unlock(&kvm->arch.kzdev_list_lock);
+ kvm_s390_pci_dev_release(zdev);
+
+ mutex_unlock(&kvm->lock);
+ mutex_unlock(&zdev->kzdev_lock);
+
+ kvm_put_kvm(kvm);
+}
+EXPORT_SYMBOL_GPL(kvm_s390_pci_unregister_kvm);
+
+void kvm_s390_pci_init_list(struct kvm *kvm)
+{
+ spin_lock_init(&kvm->arch.kzdev_list_lock);
+ INIT_LIST_HEAD(&kvm->arch.kzdev_list);
+}
+
+void kvm_s390_pci_clear_list(struct kvm *kvm)
+{
+ /*
+ * This list should already be empty, either via vfio device closures
+ * or kvm fd cleanup.
+ */
+ spin_lock(&kvm->arch.kzdev_list_lock);
+ WARN_ON_ONCE(!list_empty(&kvm->arch.kzdev_list));
+ spin_unlock(&kvm->arch.kzdev_list_lock);
+}
+
int kvm_s390_pci_init(void)
{
aift = kzalloc(sizeof(struct zpci_aift), GFP_KERNEL);
diff --git a/arch/s390/kvm/pci.h b/arch/s390/kvm/pci.h
index 9d091033fc02..fb2b91b76e0c 100644
--- a/arch/s390/kvm/pci.h
+++ b/arch/s390/kvm/pci.h
@@ -13,6 +13,7 @@
#include <linux/kvm_host.h>
#include <linux/pci.h>
#include <linux/mutex.h>
+#include <linux/kvm.h>
#include <linux/kvm_host.h>
#include <asm/airq.h>
#include <asm/cpu.h>
@@ -21,6 +22,7 @@ struct kvm_zdev {
struct zpci_dev *zdev;
struct kvm *kvm;
struct zpci_fib fib;
+ struct list_head entry;
};
struct zpci_gaite {
@@ -54,6 +56,9 @@ static inline struct kvm *kvm_s390_pci_si_to_kvm(struct zpci_aift *aift,
int kvm_s390_pci_aen_init(u8 nisc);
void kvm_s390_pci_aen_exit(void);
+void kvm_s390_pci_init_list(struct kvm *kvm);
+void kvm_s390_pci_clear_list(struct kvm *kvm);
+
int kvm_s390_pci_init(void);
void kvm_s390_pci_exit(void);
diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c
index 86cd4d8446b1..73cdc5539384 100644
--- a/arch/s390/pci/pci.c
+++ b/arch/s390/pci/pci.c
@@ -132,6 +132,7 @@ 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)
@@ -712,6 +713,7 @@ 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)
{
@@ -735,6 +737,7 @@ 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
@@ -828,6 +831,7 @@ struct zpci_dev *zpci_create_device(u32 fid, u32 fh, enum zpci_state state)
kref_init(&zdev->kref);
mutex_init(&zdev->lock);
+ mutex_init(&zdev->kzdev_lock);
rc = zpci_init_iommu(zdev);
if (rc)
--
2.27.0
On 6/6/22 22:33, Matthew Rosato wrote:
> These routines will be invoked at the time an s390x vfio-pci device is
> associated with a KVM (or when the association is removed), allowing
> the zPCI device to enable or disable load/store intepretation mode;
> this requires the host zPCI device to inform firmware of the unique
> token (GISA designation) that is associated with the owning KVM.
>
> Signed-off-by: Matthew Rosato <[email protected]>
> ---
> arch/s390/include/asm/kvm_host.h | 18 ++++
> arch/s390/include/asm/pci.h | 1 +
> arch/s390/kvm/kvm-s390.c | 15 +++
> arch/s390/kvm/pci.c | 162 +++++++++++++++++++++++++++++++
> arch/s390/kvm/pci.h | 5 +
> arch/s390/pci/pci.c | 4 +
> 6 files changed, 205 insertions(+)
>
> diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
> index 8e381603b6a7..6e83d746bae2 100644
> --- a/arch/s390/include/asm/kvm_host.h
> +++ b/arch/s390/include/asm/kvm_host.h
> @@ -19,6 +19,7 @@
> #include <linux/kvm.h>
> #include <linux/seqlock.h>
> #include <linux/module.h>
> +#include <linux/pci.h>
> #include <asm/debug.h>
> #include <asm/cpu.h>
> #include <asm/fpu/api.h>
> @@ -967,6 +968,8 @@ struct kvm_arch{
> DECLARE_BITMAP(idle_mask, KVM_MAX_VCPUS);
> struct kvm_s390_gisa_interrupt gisa_int;
> struct kvm_s390_pv pv;
> + struct list_head kzdev_list;
> + spinlock_t kzdev_list_lock;
> };
>
> #define KVM_HVA_ERR_BAD (-1UL)
> @@ -1017,4 +1020,19 @@ static inline void kvm_arch_flush_shadow_memslot(struct kvm *kvm,
> static inline void kvm_arch_vcpu_blocking(struct kvm_vcpu *vcpu) {}
> static inline void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu) {}
>
> +#define __KVM_HAVE_ARCH_VM_FREE
> +void kvm_arch_free_vm(struct kvm *kvm);
> +
> +#ifdef CONFIG_VFIO_PCI_ZDEV_KVM
> +int kvm_s390_pci_register_kvm(struct zpci_dev *zdev, struct kvm *kvm);
> +void kvm_s390_pci_unregister_kvm(struct zpci_dev *zdev);
> +#else
> +static inline int kvm_s390_pci_register_kvm(struct zpci_dev *dev,
> + struct kvm *kvm)
> +{
> + return -EPERM;
> +}
> +static inline void kvm_s390_pci_unregister_kvm(struct zpci_dev *dev) {}
> +#endif
> +
> #endif
> diff --git a/arch/s390/include/asm/pci.h b/arch/s390/include/asm/pci.h
> index 322060a75d9f..85eb0ef9d4c3 100644
> --- a/arch/s390/include/asm/pci.h
> +++ b/arch/s390/include/asm/pci.h
> @@ -194,6 +194,7 @@ struct zpci_dev {
> /* IOMMU and passthrough */
> struct s390_domain *s390_domain; /* s390 IOMMU domain data */
> struct kvm_zdev *kzdev;
> + struct mutex kzdev_lock;
I guess that since it did not exist before the lock is not there to
protect the zpci_dev struct.
May be add a comment to say what it is protecting.
> };
>
> static inline bool zdev_enabled(struct zpci_dev *zdev)
> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
> index a66da3f66114..4758bb731199 100644
> --- a/arch/s390/kvm/kvm-s390.c
> +++ b/arch/s390/kvm/kvm-s390.c
> @@ -2790,6 +2790,14 @@ static void sca_dispose(struct kvm *kvm)
> kvm->arch.sca = NULL;
> }
>
> +void kvm_arch_free_vm(struct kvm *kvm)
> +{
> + if (IS_ENABLED(CONFIG_VFIO_PCI_ZDEV_KVM))
> + kvm_s390_pci_clear_list(kvm);
> +
> + __kvm_arch_free_vm(kvm);
> +}
> +
> int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
> {
> gfp_t alloc_flags = GFP_KERNEL_ACCOUNT;
> @@ -2872,6 +2880,13 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
>
> kvm_s390_crypto_init(kvm);
>
> + if (IS_ENABLED(CONFIG_VFIO_PCI_ZDEV_KVM)) {
> + mutex_lock(&kvm->lock);
> + kvm_s390_pci_init_list(kvm);
> + kvm_s390_vcpu_pci_enable_interp(kvm);
> + mutex_unlock(&kvm->lock);
> + }
> +
> mutex_init(&kvm->arch.float_int.ais_lock);
> spin_lock_init(&kvm->arch.float_int.lock);
> for (i = 0; i < FIRQ_LIST_COUNT; i++)
> diff --git a/arch/s390/kvm/pci.c b/arch/s390/kvm/pci.c
> index b232c8cbaa81..24211741deb0 100644
> --- a/arch/s390/kvm/pci.c
> +++ b/arch/s390/kvm/pci.c
> @@ -12,7 +12,9 @@
> #include <asm/pci.h>
> #include <asm/pci_insn.h>
> #include <asm/pci_io.h>
> +#include <asm/sclp.h>
> #include "pci.h"
> +#include "kvm-s390.h"
>
> struct zpci_aift *aift;
>
> @@ -423,6 +425,166 @@ static void kvm_s390_pci_dev_release(struct zpci_dev *zdev)
> kfree(kzdev);
> }
>
> +
> +/*
> + * Register device with the specified KVM. If interpetation facilities are
> + * available, enable them and let userspace indicate whether or not they will
> + * be used (specify SHM bit to disable).
> + */
> +int kvm_s390_pci_register_kvm(struct zpci_dev *zdev, struct kvm *kvm)
> +{
> + int rc;
> +
> + if (!zdev)
> + return -EINVAL;
> +
> + mutex_lock(&zdev->kzdev_lock);
> +
> + if (zdev->kzdev || zdev->gisa != 0 || !kvm) {
> + mutex_unlock(&zdev->kzdev_lock);
> + return -EINVAL;
> + }
> +
> + kvm_get_kvm(kvm);
> +
> + mutex_lock(&kvm->lock);
Why do we need to lock KVM here?
just a question, I do not think it is a big problem.
> +
> + rc = kvm_s390_pci_dev_open(zdev);
> + if (rc)
> + goto err;
> +
> + /*
> + * If interpretation facilities aren't available, add the device to
> + * the kzdev list but don't enable for interpretation.
> + */
> + if (!kvm_s390_pci_interp_allowed())
> + goto out;
> +
> + /*
> + * If this is the first request to use an interpreted device, make the
> + * necessary vcpu changes
> + */
> + if (!kvm->arch.use_zpci_interp)
> + kvm_s390_vcpu_pci_enable_interp(kvm);
> +
> + if (zdev_enabled(zdev)) {
> + rc = zpci_disable_device(zdev);
> + if (rc)
> + goto err;
> + }
> +
> + /*
> + * Store information about the identity of the kvm guest allowed to
> + * access this device via interpretation to be used by host CLP
> + */
> + zdev->gisa = (u32)virt_to_phys(&kvm->arch.sie_page2->gisa);
> +
> + rc = zpci_enable_device(zdev);
> + if (rc)
> + goto clear_gisa;
> +
> + /* 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 clear_gisa;
> +
> +out:
> + zdev->kzdev->kvm = kvm;
> +
> + spin_lock(&kvm->arch.kzdev_list_lock);
> + list_add_tail(&zdev->kzdev->entry, &kvm->arch.kzdev_list);
> + spin_unlock(&kvm->arch.kzdev_list_lock);
> +
> + mutex_unlock(&kvm->lock);
> + mutex_unlock(&zdev->kzdev_lock);
> + return 0;
> +
> +clear_gisa:
> + zdev->gisa = 0;
> +err:
> + if (zdev->kzdev)
> + kvm_s390_pci_dev_release(zdev);
> + mutex_unlock(&kvm->lock);
> + mutex_unlock(&zdev->kzdev_lock);
> + kvm_put_kvm(kvm);
> + return rc;
> +}
> +EXPORT_SYMBOL_GPL(kvm_s390_pci_register_kvm);
> +
> +void kvm_s390_pci_unregister_kvm(struct zpci_dev *zdev)
> +{
> + struct kvm *kvm;
> +
> + if (!zdev)
> + return;
> +
> + mutex_lock(&zdev->kzdev_lock);
> +
> + if (WARN_ON(!zdev->kzdev)) {
When can this happen ?
> + mutex_unlock(&zdev->kzdev_lock);
> + return;
> + }
> +
> + kvm = zdev->kzdev->kvm;
> + mutex_lock(&kvm->lock);
> +
> + /*
> + * A 0 gisa means interpretation was never enabled, just remove the
> + * device from the list.
> + */
> + if (zdev->gisa == 0)
> + goto out;
> +
> + /* Forwarding must be turned off before interpretation */
> + if (zdev->kzdev->fib.fmt0.aibv != 0)
> + kvm_s390_pci_aif_disable(zdev, true);
> +
> + /* Remove the host CLP guest designation */
> + zdev->gisa = 0;
> +
> + if (zdev_enabled(zdev)) {
> + if (zpci_disable_device(zdev))
> + goto out;
NIT debug trace ?
> + }
> +
> + if (zpci_enable_device(zdev))
> + goto out;
NIT debug trace?
Only some questions, otherwise, LGTM
Acked-by: Pierre Morel <[email protected]>
--
Pierre Morel
IBM Lab Boeblingen
On 6/28/22 6:53 AM, Pierre Morel wrote:
>
>
> On 6/6/22 22:33, Matthew Rosato wrote:
>> These routines will be invoked at the time an s390x vfio-pci device is
>> associated with a KVM (or when the association is removed), allowing
>> the zPCI device to enable or disable load/store intepretation mode;
>> this requires the host zPCI device to inform firmware of the unique
>> token (GISA designation) that is associated with the owning KVM.
>>
>> Signed-off-by: Matthew Rosato <[email protected]>
>> ---
>> arch/s390/include/asm/kvm_host.h | 18 ++++
>> arch/s390/include/asm/pci.h | 1 +
>> arch/s390/kvm/kvm-s390.c | 15 +++
>> arch/s390/kvm/pci.c | 162 +++++++++++++++++++++++++++++++
>> arch/s390/kvm/pci.h | 5 +
>> arch/s390/pci/pci.c | 4 +
>> 6 files changed, 205 insertions(+)
>>
>> diff --git a/arch/s390/include/asm/kvm_host.h
>> b/arch/s390/include/asm/kvm_host.h
>> index 8e381603b6a7..6e83d746bae2 100644
>> --- a/arch/s390/include/asm/kvm_host.h
>> +++ b/arch/s390/include/asm/kvm_host.h
>> @@ -19,6 +19,7 @@
>> #include <linux/kvm.h>
>> #include <linux/seqlock.h>
>> #include <linux/module.h>
>> +#include <linux/pci.h>
>> #include <asm/debug.h>
>> #include <asm/cpu.h>
>> #include <asm/fpu/api.h>
>> @@ -967,6 +968,8 @@ struct kvm_arch{
>> DECLARE_BITMAP(idle_mask, KVM_MAX_VCPUS);
>> struct kvm_s390_gisa_interrupt gisa_int;
>> struct kvm_s390_pv pv;
>> + struct list_head kzdev_list;
>> + spinlock_t kzdev_list_lock;
>> };
>> #define KVM_HVA_ERR_BAD (-1UL)
>> @@ -1017,4 +1020,19 @@ static inline void
>> kvm_arch_flush_shadow_memslot(struct kvm *kvm,
>> static inline void kvm_arch_vcpu_blocking(struct kvm_vcpu *vcpu) {}
>> static inline void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu) {}
>> +#define __KVM_HAVE_ARCH_VM_FREE
>> +void kvm_arch_free_vm(struct kvm *kvm);
>> +
>> +#ifdef CONFIG_VFIO_PCI_ZDEV_KVM
>> +int kvm_s390_pci_register_kvm(struct zpci_dev *zdev, struct kvm *kvm);
>> +void kvm_s390_pci_unregister_kvm(struct zpci_dev *zdev);
>> +#else
>> +static inline int kvm_s390_pci_register_kvm(struct zpci_dev *dev,
>> + struct kvm *kvm)
>> +{
>> + return -EPERM;
>> +}
>> +static inline void kvm_s390_pci_unregister_kvm(struct zpci_dev *dev) {}
>> +#endif
>> +
>> #endif
>> diff --git a/arch/s390/include/asm/pci.h b/arch/s390/include/asm/pci.h
>> index 322060a75d9f..85eb0ef9d4c3 100644
>> --- a/arch/s390/include/asm/pci.h
>> +++ b/arch/s390/include/asm/pci.h
>> @@ -194,6 +194,7 @@ struct zpci_dev {
>> /* IOMMU and passthrough */
>> struct s390_domain *s390_domain; /* s390 IOMMU domain data */
>> struct kvm_zdev *kzdev;
>> + struct mutex kzdev_lock;
>
> I guess that since it did not exist before the lock is not there to
> protect the zpci_dev struct.
Right, not the zpci_dev itself but it is protecting the contents of the
kzdev (including the pointer to the zdev e.g. kzdev->zdev)
> May be add a comment to say what it is protecting.
Sure
>
>
>> };
>> static inline bool zdev_enabled(struct zpci_dev *zdev)
>> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
>> index a66da3f66114..4758bb731199 100644
>> --- a/arch/s390/kvm/kvm-s390.c
>> +++ b/arch/s390/kvm/kvm-s390.c
>> @@ -2790,6 +2790,14 @@ static void sca_dispose(struct kvm *kvm)
>> kvm->arch.sca = NULL;
>> }
>> +void kvm_arch_free_vm(struct kvm *kvm)
>> +{
>> + if (IS_ENABLED(CONFIG_VFIO_PCI_ZDEV_KVM))
>> + kvm_s390_pci_clear_list(kvm);
>> +
>> + __kvm_arch_free_vm(kvm);
>> +}
>> +
>> int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
>> {
>> gfp_t alloc_flags = GFP_KERNEL_ACCOUNT;
>> @@ -2872,6 +2880,13 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned
>> long type)
>> kvm_s390_crypto_init(kvm);
>> + if (IS_ENABLED(CONFIG_VFIO_PCI_ZDEV_KVM)) {
>> + mutex_lock(&kvm->lock);
>> + kvm_s390_pci_init_list(kvm);
>> + kvm_s390_vcpu_pci_enable_interp(kvm);
>> + mutex_unlock(&kvm->lock);
>> + }
>> +
>> mutex_init(&kvm->arch.float_int.ais_lock);
>> spin_lock_init(&kvm->arch.float_int.lock);
>> for (i = 0; i < FIRQ_LIST_COUNT; i++)
>> diff --git a/arch/s390/kvm/pci.c b/arch/s390/kvm/pci.c
>> index b232c8cbaa81..24211741deb0 100644
>> --- a/arch/s390/kvm/pci.c
>> +++ b/arch/s390/kvm/pci.c
>> @@ -12,7 +12,9 @@
>> #include <asm/pci.h>
>> #include <asm/pci_insn.h>
>> #include <asm/pci_io.h>
>> +#include <asm/sclp.h>
>> #include "pci.h"
>> +#include "kvm-s390.h"
>> struct zpci_aift *aift;
>> @@ -423,6 +425,166 @@ static void kvm_s390_pci_dev_release(struct
>> zpci_dev *zdev)
>> kfree(kzdev);
>> }
>> +
>> +/*
>> + * Register device with the specified KVM. If interpetation
>> facilities are
>> + * available, enable them and let userspace indicate whether or not
>> they will
>> + * be used (specify SHM bit to disable).
>> + */
>> +int kvm_s390_pci_register_kvm(struct zpci_dev *zdev, struct kvm *kvm)
>> +{
>> + int rc;
>> +
>> + if (!zdev)
>> + return -EINVAL;
>> +
>> + mutex_lock(&zdev->kzdev_lock);
>> +
>> + if (zdev->kzdev || zdev->gisa != 0 || !kvm) {
>> + mutex_unlock(&zdev->kzdev_lock);
>> + return -EINVAL;
>> + }
>> +
>> + kvm_get_kvm(kvm);
>> +
>> + mutex_lock(&kvm->lock);
>
> Why do we need to lock KVM here?
Hmm, good point, now that we get a reference this seems unnecessary
>
> just a question, I do not think it is a big problem.
>
>> +
>> + rc = kvm_s390_pci_dev_open(zdev);
>> + if (rc)
>> + goto err;
>> +
>> + /*
>> + * If interpretation facilities aren't available, add the device to
>> + * the kzdev list but don't enable for interpretation.
>> + */
>> + if (!kvm_s390_pci_interp_allowed())
>> + goto out;
>> +
>> + /*
>> + * If this is the first request to use an interpreted device,
>> make the
>> + * necessary vcpu changes
>> + */
>> + if (!kvm->arch.use_zpci_interp)
>> + kvm_s390_vcpu_pci_enable_interp(kvm);
>> +
>> + if (zdev_enabled(zdev)) {
>> + rc = zpci_disable_device(zdev);
>> + if (rc)
>> + goto err;
>> + }
>> +
>> + /*
>> + * Store information about the identity of the kvm guest allowed to
>> + * access this device via interpretation to be used by host CLP
>> + */
>> + zdev->gisa = (u32)virt_to_phys(&kvm->arch.sie_page2->gisa);
>> +
>> + rc = zpci_enable_device(zdev);
>> + if (rc)
>> + goto clear_gisa;
>> +
>> + /* 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 clear_gisa;
>> +
>> +out:
>> + zdev->kzdev->kvm = kvm;
>> +
>> + spin_lock(&kvm->arch.kzdev_list_lock);
>> + list_add_tail(&zdev->kzdev->entry, &kvm->arch.kzdev_list);
>> + spin_unlock(&kvm->arch.kzdev_list_lock);
>> +
>> + mutex_unlock(&kvm->lock);
>> + mutex_unlock(&zdev->kzdev_lock);
>> + return 0;
>> +
>> +clear_gisa:
>> + zdev->gisa = 0;
>> +err:
>> + if (zdev->kzdev)
>> + kvm_s390_pci_dev_release(zdev);
>> + mutex_unlock(&kvm->lock);
>> + mutex_unlock(&zdev->kzdev_lock);
>> + kvm_put_kvm(kvm);
>> + return rc;
>> +}
>> +EXPORT_SYMBOL_GPL(kvm_s390_pci_register_kvm);
>> +
>> +void kvm_s390_pci_unregister_kvm(struct zpci_dev *zdev)
>> +{
>> + struct kvm *kvm;
>> +
>> + if (!zdev)
>> + return;
>> +
>> + mutex_lock(&zdev->kzdev_lock);
>> +
>> + if (WARN_ON(!zdev->kzdev)) {
>
> When can this happen ?
>
It cannot today, nor should it ever (hence the WARN_ON) -- if we do,
it's a case of programming error introduced somewhere (vfio has a KVM
reference but we never built a kzdev via kvm_s390_pci_register_kvm or
lost it somehow)
>> + mutex_unlock(&zdev->kzdev_lock);
>> + return;
>> + }
>> +
>> + kvm = zdev->kzdev->kvm;
>> + mutex_lock(&kvm->lock);
>> +
>> + /*
>> + * A 0 gisa means interpretation was never enabled, just remove the
>> + * device from the list.
>> + */
>> + if (zdev->gisa == 0)
>> + goto out;
>> +
>> + /* Forwarding must be turned off before interpretation */
>> + if (zdev->kzdev->fib.fmt0.aibv != 0)
>> + kvm_s390_pci_aif_disable(zdev, true);
>> +
>> + /* Remove the host CLP guest designation */
>> + zdev->gisa = 0;
>> +
>> + if (zdev_enabled(zdev)) {
>> + if (zpci_disable_device(zdev))
>> + goto out;
>
> NIT debug trace ?
We should at least get a trace entry in from clp_disable_fh() if
something goes wrong here.
>
>> + }
>> +
>> + if (zpci_enable_device(zdev))
>> + goto out;
>
> NIT debug trace?
And similarly, a trace entry from clp_enable_fh() here. So I think
these are OK for now.
I am consdering a follow-on to add new s390dbf entries for 'kvm-pci' or
so, these might make sense there for additional context, but let's leave
that for after this series.
>
> Only some questions, otherwise, LGTM
>
> Acked-by: Pierre Morel <[email protected]>
>
Thanks!