| Message ID | 20220404181726.60291-6-mjrosato@linux.ibm.com |
|---|---|
| State | New |
| Headers | show |
| Series | s390x/pci: zPCI interpretation support | expand |
On 4/4/22 20:17, Matthew Rosato wrote: > If the appropriate CPU facilty is available as well as the necessary > ZPCI_OP ioctl, then the underlying KVM host will enable load/store > intepretation for any guest device without a SHM bit in the guest > function handle. For a device that will be using interpretation > support, ensure the guest function handle matches the host function > handle; this value is re-checked every time the guest issues a SET PCI FN > to enable the guest device as it is the only opportunity to reflect > function handle changes. > > By default, unless interpret=off is specified, interpretation support will > always be assumed and exploited if the necessary ioctl and features are > available on the host kernel. When these are unavailable, we will silently > revert to the interception model; this allows existing guest configurations > to work unmodified on hosts with and without zPCI interpretation support, > allowing QEMU to choose the best support model available. > > Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com> > --- > hw/s390x/meson.build | 1 + > hw/s390x/s390-pci-bus.c | 66 ++++++++++++++++++++++++++++++++- > hw/s390x/s390-pci-inst.c | 12 ++++++ > hw/s390x/s390-pci-kvm.c | 21 +++++++++++ > include/hw/s390x/s390-pci-bus.h | 1 + > include/hw/s390x/s390-pci-kvm.h | 24 ++++++++++++ > target/s390x/kvm/kvm.c | 7 ++++ > target/s390x/kvm/kvm_s390x.h | 1 + > 8 files changed, 132 insertions(+), 1 deletion(-) > create mode 100644 hw/s390x/s390-pci-kvm.c > create mode 100644 include/hw/s390x/s390-pci-kvm.h > ...snip... > if (s390_pci_msix_init(pbdev)) { > @@ -1360,6 +1423,7 @@ static Property s390_pci_device_properties[] = { > DEFINE_PROP_UINT16("uid", S390PCIBusDevice, uid, UID_UNDEFINED), > DEFINE_PROP_S390_PCI_FID("fid", S390PCIBusDevice, fid), > DEFINE_PROP_STRING("target", S390PCIBusDevice, target), > + DEFINE_PROP_BOOL("interpret", S390PCIBusDevice, interp, true), > DEFINE_PROP_END_OF_LIST(), > }; > > diff --git a/hw/s390x/s390-pci-inst.c b/hw/s390x/s390-pci-inst.c > index 6d400d4147..c898c8abe9 100644 > --- a/hw/s390x/s390-pci-inst.c > +++ b/hw/s390x/s390-pci-inst.c > @@ -18,6 +18,8 @@ > #include "sysemu/hw_accel.h" > #include "hw/s390x/s390-pci-inst.h" > #include "hw/s390x/s390-pci-bus.h" > +#include "hw/s390x/s390-pci-kvm.h" > +#include "hw/s390x/s390-pci-vfio.h" > #include "hw/s390x/tod.h" > > #ifndef DEBUG_S390PCI_INST > @@ -246,6 +248,16 @@ int clp_service_call(S390CPU *cpu, uint8_t r2, uintptr_t ra) > goto out; > } > > + /* > + * Take this opportunity to make sure we still have an accurate > + * host fh. It's possible part of the handle changed while the > + * device was disabled to the guest (e.g. vfio hot reset for > + * ISM during plug) > + */ > + if (pbdev->interp) { > + /* Take this opportunity to make sure we are sync'd with host */ > + s390_pci_get_host_fh(pbdev, &pbdev->fh); > + } > pbdev->fh |= FH_MASK_ENABLE; Are we sure here that the PCI device is always enabled? Shouldn't we check? > pbdev->state = ZPCI_FS_ENABLED; > stl_p(&ressetpci->fh, pbdev->fh); > diff --git a/hw/s390x/s390-pci-kvm.c b/hw/s390x/s390-pci-kvm.c > new file mode 100644 > index 0000000000..8bfce9ef18 > --- /dev/null > +++ b/hw/s390x/s390-pci-kvm.c > @@ -0,0 +1,21 @@ > +/* > + * s390 zPCI KVM interfaces > + * > + * Copyright 2022 IBM Corp. > + * Author(s): Matthew Rosato <mjrosato@linux.ibm.com> > + * > + * This work is licensed under the terms of the GNU GPL, version 2 or (at > + * your option) any later version. See the COPYING file in the top-level > + * directory. > + */ > + > +#include "qemu/osdep.h" > + > +#include "kvm/kvm_s390x.h" > +#include "hw/s390x/s390-pci-kvm.h" > +#include "cpu_models.h" > + > +bool s390_pci_kvm_interp_allowed(void) > +{ > + return s390_has_feat(S390_FEAT_ZPCI_INTERP) && kvm_s390_get_zpci_op(); > +} ZPCI is not supported by the PV currently but I do not see what could prevent it to be enable in the future. As the code of QEMU zPCI is not PV compatible, I would like to add a check for PV. ... && !s390_is_pv()) > diff --git a/include/hw/s390x/s390-pci-bus.h b/include/hw/s390x/s390-pci-bus.h > index da3cde2bb4..a9843dfe97 100644 > --- a/include/hw/s390x/s390-pci-bus.h > +++ b/include/hw/s390x/s390-pci-bus.h > @@ -350,6 +350,7 @@ struct S390PCIBusDevice { > IndAddr *indicator; > bool pci_unplug_request_processed; > bool unplug_requested; > + bool interp; > QTAILQ_ENTRY(S390PCIBusDevice) link; > }; > ...snip...
On 4/19/22 3:47 PM, Pierre Morel wrote: > > > On 4/4/22 20:17, Matthew Rosato wrote: >> If the appropriate CPU facilty is available as well as the necessary >> ZPCI_OP ioctl, then the underlying KVM host will enable load/store >> intepretation for any guest device without a SHM bit in the guest >> function handle. For a device that will be using interpretation >> support, ensure the guest function handle matches the host function >> handle; this value is re-checked every time the guest issues a SET PCI FN >> to enable the guest device as it is the only opportunity to reflect >> function handle changes. >> >> By default, unless interpret=off is specified, interpretation support >> will >> always be assumed and exploited if the necessary ioctl and features are >> available on the host kernel. When these are unavailable, we will >> silently >> revert to the interception model; this allows existing guest >> configurations >> to work unmodified on hosts with and without zPCI interpretation support, >> allowing QEMU to choose the best support model available. >> >> Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com> >> --- >> hw/s390x/meson.build | 1 + >> hw/s390x/s390-pci-bus.c | 66 ++++++++++++++++++++++++++++++++- >> hw/s390x/s390-pci-inst.c | 12 ++++++ >> hw/s390x/s390-pci-kvm.c | 21 +++++++++++ >> include/hw/s390x/s390-pci-bus.h | 1 + >> include/hw/s390x/s390-pci-kvm.h | 24 ++++++++++++ >> target/s390x/kvm/kvm.c | 7 ++++ >> target/s390x/kvm/kvm_s390x.h | 1 + >> 8 files changed, 132 insertions(+), 1 deletion(-) >> create mode 100644 hw/s390x/s390-pci-kvm.c >> create mode 100644 include/hw/s390x/s390-pci-kvm.h >> > > ...snip... > >> if (s390_pci_msix_init(pbdev)) { >> @@ -1360,6 +1423,7 @@ static Property s390_pci_device_properties[] = { >> DEFINE_PROP_UINT16("uid", S390PCIBusDevice, uid, UID_UNDEFINED), >> DEFINE_PROP_S390_PCI_FID("fid", S390PCIBusDevice, fid), >> DEFINE_PROP_STRING("target", S390PCIBusDevice, target), >> + DEFINE_PROP_BOOL("interpret", S390PCIBusDevice, interp, true), >> DEFINE_PROP_END_OF_LIST(), >> }; >> diff --git a/hw/s390x/s390-pci-inst.c b/hw/s390x/s390-pci-inst.c >> index 6d400d4147..c898c8abe9 100644 >> --- a/hw/s390x/s390-pci-inst.c >> +++ b/hw/s390x/s390-pci-inst.c >> @@ -18,6 +18,8 @@ >> #include "sysemu/hw_accel.h" >> #include "hw/s390x/s390-pci-inst.h" >> #include "hw/s390x/s390-pci-bus.h" >> +#include "hw/s390x/s390-pci-kvm.h" >> +#include "hw/s390x/s390-pci-vfio.h" >> #include "hw/s390x/tod.h" >> #ifndef DEBUG_S390PCI_INST >> @@ -246,6 +248,16 @@ int clp_service_call(S390CPU *cpu, uint8_t r2, >> uintptr_t ra) >> goto out; >> } >> + /* >> + * Take this opportunity to make sure we still have an >> accurate >> + * host fh. It's possible part of the handle changed >> while the >> + * device was disabled to the guest (e.g. vfio hot reset for >> + * ISM during plug) >> + */ >> + if (pbdev->interp) { >> + /* Take this opportunity to make sure we are sync'd >> with host */ >> + s390_pci_get_host_fh(pbdev, &pbdev->fh); >> + } >> pbdev->fh |= FH_MASK_ENABLE; > > Are we sure here that the PCI device is always enabled? > Shouldn't we check? I guess you mean the host device? Interesting thought. So, to be clear, the idea on setting FH_MASK_ENABLE here is that we are handling a guest CLP SET PCI FN enable so the guest fh should always have FH_MASK_ENABLE set if we return CLP_RC_OK to the guest. But for interpretation, if we find the host function is disabled, I suppose we could return an error on the guest CLP (not sure which error yet); otherwise, if we return the force-enabled handle and CLP_RC_OK as we do here then the guest will just get errors attempting to use it.
On 4/20/22 17:12, Matthew Rosato wrote: > On 4/19/22 3:47 PM, Pierre Morel wrote: >> >> >> On 4/4/22 20:17, Matthew Rosato wrote: >>> If the appropriate CPU facilty is available as well as the necessary >>> ZPCI_OP ioctl, then the underlying KVM host will enable load/store >>> intepretation for any guest device without a SHM bit in the guest >>> function handle. For a device that will be using interpretation >>> support, ensure the guest function handle matches the host function >>> handle; this value is re-checked every time the guest issues a SET >>> PCI FN >>> to enable the guest device as it is the only opportunity to reflect >>> function handle changes. >>> >>> By default, unless interpret=off is specified, interpretation support >>> will >>> always be assumed and exploited if the necessary ioctl and features are >>> available on the host kernel. When these are unavailable, we will >>> silently >>> revert to the interception model; this allows existing guest >>> configurations >>> to work unmodified on hosts with and without zPCI interpretation >>> support, >>> allowing QEMU to choose the best support model available. >>> >>> Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com> >>> --- >>> hw/s390x/meson.build | 1 + >>> hw/s390x/s390-pci-bus.c | 66 ++++++++++++++++++++++++++++++++- >>> hw/s390x/s390-pci-inst.c | 12 ++++++ >>> hw/s390x/s390-pci-kvm.c | 21 +++++++++++ >>> include/hw/s390x/s390-pci-bus.h | 1 + >>> include/hw/s390x/s390-pci-kvm.h | 24 ++++++++++++ >>> target/s390x/kvm/kvm.c | 7 ++++ >>> target/s390x/kvm/kvm_s390x.h | 1 + >>> 8 files changed, 132 insertions(+), 1 deletion(-) >>> create mode 100644 hw/s390x/s390-pci-kvm.c >>> create mode 100644 include/hw/s390x/s390-pci-kvm.h >>> >> >> ...snip... >> >>> if (s390_pci_msix_init(pbdev)) { >>> @@ -1360,6 +1423,7 @@ static Property s390_pci_device_properties[] = { >>> DEFINE_PROP_UINT16("uid", S390PCIBusDevice, uid, UID_UNDEFINED), >>> DEFINE_PROP_S390_PCI_FID("fid", S390PCIBusDevice, fid), >>> DEFINE_PROP_STRING("target", S390PCIBusDevice, target), >>> + DEFINE_PROP_BOOL("interpret", S390PCIBusDevice, interp, true), >>> DEFINE_PROP_END_OF_LIST(), >>> }; >>> diff --git a/hw/s390x/s390-pci-inst.c b/hw/s390x/s390-pci-inst.c >>> index 6d400d4147..c898c8abe9 100644 >>> --- a/hw/s390x/s390-pci-inst.c >>> +++ b/hw/s390x/s390-pci-inst.c >>> @@ -18,6 +18,8 @@ >>> #include "sysemu/hw_accel.h" >>> #include "hw/s390x/s390-pci-inst.h" >>> #include "hw/s390x/s390-pci-bus.h" >>> +#include "hw/s390x/s390-pci-kvm.h" >>> +#include "hw/s390x/s390-pci-vfio.h" >>> #include "hw/s390x/tod.h" >>> #ifndef DEBUG_S390PCI_INST >>> @@ -246,6 +248,16 @@ int clp_service_call(S390CPU *cpu, uint8_t r2, >>> uintptr_t ra) >>> goto out; >>> } >>> + /* >>> + * Take this opportunity to make sure we still have an >>> accurate >>> + * host fh. It's possible part of the handle changed >>> while the >>> + * device was disabled to the guest (e.g. vfio hot reset >>> for >>> + * ISM during plug) >>> + */ >>> + if (pbdev->interp) { >>> + /* Take this opportunity to make sure we are sync'd >>> with host */ >>> + s390_pci_get_host_fh(pbdev, &pbdev->fh); Here we should check the return value and, AFAIU, assume that the device disappear if it did return false. >>> + } >>> pbdev->fh |= FH_MASK_ENABLE; >> >> Are we sure here that the PCI device is always enabled? >> Shouldn't we check? > > I guess you mean the host device? Interesting thought. > > So, to be clear, the idea on setting FH_MASK_ENABLE here is that we are > handling a guest CLP SET PCI FN enable so the guest fh should always > have FH_MASK_ENABLE set if we return CLP_RC_OK to the guest. > > But for interpretation, if we find the host function is disabled, I > suppose we could return an error on the guest CLP (not sure which error > yet); otherwise, if we return the force-enabled handle and CLP_RC_OK as > we do here then the guest will just get errors attempting to use it. hum, in this case can't we have a loop on clp enable->error->clp disable->clp enable->error... I think we should return an error if what the guest asked for could not be done. > > >
diff --git a/hw/s390x/meson.build b/hw/s390x/meson.build index 28484256ec..6e6e47fcda 100644 --- a/hw/s390x/meson.build +++ b/hw/s390x/meson.build @@ -23,6 +23,7 @@ s390x_ss.add(when: 'CONFIG_KVM', if_true: files( 's390-skeys-kvm.c', 's390-stattrib-kvm.c', 'pv.c', + 's390-pci-kvm.c', )) s390x_ss.add(when: 'CONFIG_TCG', if_true: files( 'tod-tcg.c', diff --git a/hw/s390x/s390-pci-bus.c b/hw/s390x/s390-pci-bus.c index 4b2bdd94b3..156051e6e9 100644 --- a/hw/s390x/s390-pci-bus.c +++ b/hw/s390x/s390-pci-bus.c @@ -16,6 +16,7 @@ #include "qapi/visitor.h" #include "hw/s390x/s390-pci-bus.h" #include "hw/s390x/s390-pci-inst.h" +#include "hw/s390x/s390-pci-kvm.h" #include "hw/s390x/s390-pci-vfio.h" #include "hw/pci/pci_bus.h" #include "hw/qdev-properties.h" @@ -971,12 +972,51 @@ static void s390_pci_update_subordinate(PCIDevice *dev, uint32_t nr) } } +static int s390_pci_interp_plug(S390pciState *s, S390PCIBusDevice *pbdev) +{ + uint32_t idx, fh; + + if (!s390_pci_get_host_fh(pbdev, &fh)) { + return -EPERM; + } + + /* + * The host device is already in an enabled state, but we always present + * the initial device state to the guest as disabled (ZPCI_FS_DISABLED). + * Therefore, mask off the enable bit from the passthrough handle until + * the guest issues a CLP SET PCI FN later to enable the device. + */ + pbdev->fh = fh & ~FH_MASK_ENABLE; + + /* Next, see if the idx is already in-use */ + idx = pbdev->fh & FH_MASK_INDEX; + if (pbdev->idx != idx) { + if (s390_pci_find_dev_by_idx(s, idx)) { + return -EINVAL; + } + /* + * Update the idx entry with the passed through idx + * If the relinquished idx is lower than next_idx, use it + * to replace next_idx + */ + g_hash_table_remove(s->zpci_table, &pbdev->idx); + if (idx < s->next_idx) { + s->next_idx = idx; + } + pbdev->idx = idx; + g_hash_table_insert(s->zpci_table, &pbdev->idx, pbdev); + } + + return 0; +} + static void s390_pcihost_plug(HotplugHandler *hotplug_dev, DeviceState *dev, Error **errp) { S390pciState *s = S390_PCI_HOST_BRIDGE(hotplug_dev); PCIDevice *pdev = NULL; S390PCIBusDevice *pbdev = NULL; + int rc; if (object_dynamic_cast(OBJECT(dev), TYPE_PCI_BRIDGE)) { PCIBridge *pb = PCI_BRIDGE(dev); @@ -1022,12 +1062,35 @@ static void s390_pcihost_plug(HotplugHandler *hotplug_dev, DeviceState *dev, set_pbdev_info(pbdev); if (object_dynamic_cast(OBJECT(dev), "vfio-pci")) { - pbdev->fh |= FH_SHM_VFIO; + /* + * By default, interpretation is always requested; if the available + * facilities indicate it is not available, fallback to the + * interception model. + */ + if (pbdev->interp) { + if (s390_pci_kvm_interp_allowed()) { + rc = s390_pci_interp_plug(s, pbdev); + if (rc) { + error_setg(errp, "Plug failed for zPCI device in " + "interpretation mode: %d", rc); + return; + } + } else { + DPRINTF("zPCI interpretation facilities missing.\n"); + pbdev->interp = false; + } + } pbdev->iommu->dma_limit = s390_pci_start_dma_count(s, pbdev); /* Fill in CLP information passed via the vfio region */ s390_pci_get_clp_info(pbdev); + if (!pbdev->interp) { + /* Do vfio passthrough but intercept for I/O */ + pbdev->fh |= FH_SHM_VFIO; + } } else { pbdev->fh |= FH_SHM_EMUL; + /* Always intercept emulated devices */ + pbdev->interp = false; } if (s390_pci_msix_init(pbdev)) { @@ -1360,6 +1423,7 @@ static Property s390_pci_device_properties[] = { DEFINE_PROP_UINT16("uid", S390PCIBusDevice, uid, UID_UNDEFINED), DEFINE_PROP_S390_PCI_FID("fid", S390PCIBusDevice, fid), DEFINE_PROP_STRING("target", S390PCIBusDevice, target), + DEFINE_PROP_BOOL("interpret", S390PCIBusDevice, interp, true), DEFINE_PROP_END_OF_LIST(), }; diff --git a/hw/s390x/s390-pci-inst.c b/hw/s390x/s390-pci-inst.c index 6d400d4147..c898c8abe9 100644 --- a/hw/s390x/s390-pci-inst.c +++ b/hw/s390x/s390-pci-inst.c @@ -18,6 +18,8 @@ #include "sysemu/hw_accel.h" #include "hw/s390x/s390-pci-inst.h" #include "hw/s390x/s390-pci-bus.h" +#include "hw/s390x/s390-pci-kvm.h" +#include "hw/s390x/s390-pci-vfio.h" #include "hw/s390x/tod.h" #ifndef DEBUG_S390PCI_INST @@ -246,6 +248,16 @@ int clp_service_call(S390CPU *cpu, uint8_t r2, uintptr_t ra) goto out; } + /* + * Take this opportunity to make sure we still have an accurate + * host fh. It's possible part of the handle changed while the + * device was disabled to the guest (e.g. vfio hot reset for + * ISM during plug) + */ + if (pbdev->interp) { + /* Take this opportunity to make sure we are sync'd with host */ + s390_pci_get_host_fh(pbdev, &pbdev->fh); + } pbdev->fh |= FH_MASK_ENABLE; pbdev->state = ZPCI_FS_ENABLED; stl_p(&ressetpci->fh, pbdev->fh); diff --git a/hw/s390x/s390-pci-kvm.c b/hw/s390x/s390-pci-kvm.c new file mode 100644 index 0000000000..8bfce9ef18 --- /dev/null +++ b/hw/s390x/s390-pci-kvm.c @@ -0,0 +1,21 @@ +/* + * s390 zPCI KVM interfaces + * + * Copyright 2022 IBM Corp. + * Author(s): Matthew Rosato <mjrosato@linux.ibm.com> + * + * This work is licensed under the terms of the GNU GPL, version 2 or (at + * your option) any later version. See the COPYING file in the top-level + * directory. + */ + +#include "qemu/osdep.h" + +#include "kvm/kvm_s390x.h" +#include "hw/s390x/s390-pci-kvm.h" +#include "cpu_models.h" + +bool s390_pci_kvm_interp_allowed(void) +{ + return s390_has_feat(S390_FEAT_ZPCI_INTERP) && kvm_s390_get_zpci_op(); +} diff --git a/include/hw/s390x/s390-pci-bus.h b/include/hw/s390x/s390-pci-bus.h index da3cde2bb4..a9843dfe97 100644 --- a/include/hw/s390x/s390-pci-bus.h +++ b/include/hw/s390x/s390-pci-bus.h @@ -350,6 +350,7 @@ struct S390PCIBusDevice { IndAddr *indicator; bool pci_unplug_request_processed; bool unplug_requested; + bool interp; QTAILQ_ENTRY(S390PCIBusDevice) link; }; diff --git a/include/hw/s390x/s390-pci-kvm.h b/include/hw/s390x/s390-pci-kvm.h new file mode 100644 index 0000000000..80a2e7d0ca --- /dev/null +++ b/include/hw/s390x/s390-pci-kvm.h @@ -0,0 +1,24 @@ +/* + * s390 PCI KVM interfaces + * + * Copyright 2022 IBM Corp. + * Author(s): Matthew Rosato <mjrosato@linux.ibm.com> + * + * This work is licensed under the terms of the GNU GPL, version 2 or (at + * your option) any later version. See the COPYING file in the top-level + * directory. + */ + +#ifndef HW_S390_PCI_KVM_H +#define HW_S390_PCI_KVM_H + +#ifdef CONFIG_KVM +bool s390_pci_kvm_interp_allowed(void); +#else +static inline bool s390_pci_kvm_interp_allowed(void) +{ + return false; +} +#endif + +#endif diff --git a/target/s390x/kvm/kvm.c b/target/s390x/kvm/kvm.c index 0357bfda89..288fbd1d75 100644 --- a/target/s390x/kvm/kvm.c +++ b/target/s390x/kvm/kvm.c @@ -157,6 +157,7 @@ static int cap_ri; static int cap_hpage_1m; static int cap_vcpu_resets; static int cap_protected; +static int cap_zpci_op; static int active_cmma; @@ -358,6 +359,7 @@ int kvm_arch_init(MachineState *ms, KVMState *s) cap_s390_irq = kvm_check_extension(s, KVM_CAP_S390_INJECT_IRQ); cap_vcpu_resets = kvm_check_extension(s, KVM_CAP_S390_VCPU_RESETS); cap_protected = kvm_check_extension(s, KVM_CAP_S390_PROTECTED); + cap_zpci_op = kvm_check_extension(s, KVM_CAP_S390_ZPCI_OP); kvm_vm_enable_cap(s, KVM_CAP_S390_USER_SIGP, 0); kvm_vm_enable_cap(s, KVM_CAP_S390_VECTOR_REGISTERS, 0); @@ -2567,3 +2569,8 @@ bool kvm_arch_cpu_check_are_resettable(void) { return true; } + +int kvm_s390_get_zpci_op(void) +{ + return cap_zpci_op; +} diff --git a/target/s390x/kvm/kvm_s390x.h b/target/s390x/kvm/kvm_s390x.h index 05a5e1e6f4..aaae8570de 100644 --- a/target/s390x/kvm/kvm_s390x.h +++ b/target/s390x/kvm/kvm_s390x.h @@ -27,6 +27,7 @@ void kvm_s390_vcpu_interrupt_pre_save(S390CPU *cpu); int kvm_s390_vcpu_interrupt_post_load(S390CPU *cpu); int kvm_s390_get_hpage_1m(void); int kvm_s390_get_ri(void); +int kvm_s390_get_zpci_op(void); int kvm_s390_get_clock(uint8_t *tod_high, uint64_t *tod_clock); int kvm_s390_get_clock_ext(uint8_t *tod_high, uint64_t *tod_clock); int kvm_s390_set_clock(uint8_t tod_high, uint64_t tod_clock);
If the appropriate CPU facilty is available as well as the necessary ZPCI_OP ioctl, then the underlying KVM host will enable load/store intepretation for any guest device without a SHM bit in the guest function handle. For a device that will be using interpretation support, ensure the guest function handle matches the host function handle; this value is re-checked every time the guest issues a SET PCI FN to enable the guest device as it is the only opportunity to reflect function handle changes. By default, unless interpret=off is specified, interpretation support will always be assumed and exploited if the necessary ioctl and features are available on the host kernel. When these are unavailable, we will silently revert to the interception model; this allows existing guest configurations to work unmodified on hosts with and without zPCI interpretation support, allowing QEMU to choose the best support model available. Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com> --- hw/s390x/meson.build | 1 + hw/s390x/s390-pci-bus.c | 66 ++++++++++++++++++++++++++++++++- hw/s390x/s390-pci-inst.c | 12 ++++++ hw/s390x/s390-pci-kvm.c | 21 +++++++++++ include/hw/s390x/s390-pci-bus.h | 1 + include/hw/s390x/s390-pci-kvm.h | 24 ++++++++++++ target/s390x/kvm/kvm.c | 7 ++++ target/s390x/kvm/kvm_s390x.h | 1 + 8 files changed, 132 insertions(+), 1 deletion(-) create mode 100644 hw/s390x/s390-pci-kvm.c create mode 100644 include/hw/s390x/s390-pci-kvm.h