| Message ID | 20211006105827.15217-4-michal.orzel@arm.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Expose PMU to the guests | expand |
On 6 Oct 2021, at 11:58, Michal Orzel <michal.orzel@arm.com<mailto:michal.orzel@arm.com>> wrote: Add parameter vpmu to xl domain configuration syntax to enable the access to PMU registers by disabling the PMU traps(currently only for ARM). The current status is that the PMU registers are not virtualized and the physical registers are directly accessible when this parameter is enabled. There is no interrupt support and Xen will not save/restore the register values on context switches. Please note that this feature is experimental. Signed-off-by: Michal Orzel <michal.orzel@arm.com<mailto:michal.orzel@arm.com>> Signed-off-by: Julien Grall <julien@xen.org<mailto:julien@xen.org>> --- docs/man/xl.cfg.5.pod.in | 17 +++++++++++++++++ tools/golang/xenlight/helpers.gen.go | 6 ++++++ tools/golang/xenlight/types.gen.go | 1 + tools/include/libxl.h | 6 ++++++ tools/libs/light/libxl_create.c | 4 ++++ tools/libs/light/libxl_types.idl | 2 ++ tools/ocaml/libs/xc/xenctrl.ml | 1 + tools/ocaml/libs/xc/xenctrl.mli | 1 + tools/xl/xl_parse.c | 2 ++ xen/arch/arm/domain.c | 10 ++++++++-- xen/arch/arm/setup.c | 1 + xen/arch/x86/domain.c | 6 ++++++ xen/common/domain.c | 9 ++++++++- xen/include/asm-arm/domain.h | 1 + xen/include/public/domctl.h | 5 ++++- 15 files changed, 68 insertions(+), 4 deletions(-) Acked-by: Christian Lindig <christian.lindig@citrix.com<mailto:christian.lindig@citrix.com>>
On 06.10.2021 12:58, Michal Orzel wrote: > --- a/xen/arch/x86/domain.c > +++ b/xen/arch/x86/domain.c > @@ -692,6 +692,12 @@ int arch_sanitise_domain_config(struct xen_domctl_createdomain *config) > return -EINVAL; > } > > + if ( config->flags & XEN_DOMCTL_CDF_vpmu ) > + { > + dprintk(XENLOG_INFO, "vpmu support not ready yet\n"); > + return -EINVAL; > + } I consider this message potentially misleading (as x86 does have vPMU support, it merely doesn't get enabled this way). But isn't this redundant with ... > @@ -534,6 +535,12 @@ static int sanitise_domain_config(struct xen_domctl_createdomain *config) > return -EINVAL; > } > > + if ( vpmu && !vpmu_is_available ) > + { > + dprintk(XENLOG_INFO, "vpmu requested but not available\n"); > + return -EINVAL; > + } ... this? (This message is again potentially misleading.) > --- a/xen/include/public/domctl.h > +++ b/xen/include/public/domctl.h > @@ -70,9 +70,12 @@ struct xen_domctl_createdomain { > #define XEN_DOMCTL_CDF_iommu (1U<<_XEN_DOMCTL_CDF_iommu) > #define _XEN_DOMCTL_CDF_nested_virt 6 > #define XEN_DOMCTL_CDF_nested_virt (1U << _XEN_DOMCTL_CDF_nested_virt) > +/* Should we expose the vPMU to the guest? */ > +#define _XEN_DOMCTL_CDF_vpmu 7 > +#define XEN_DOMCTL_CDF_vpmu (1U << _XEN_DOMCTL_CDF_vpmu) Like for the earlier patch, I think we should stop with the bad habit of defining both the bit position and the mask separately. Jan
Hi Jan, On 07.10.2021 10:03, Jan Beulich wrote: > On 06.10.2021 12:58, Michal Orzel wrote: >> --- a/xen/arch/x86/domain.c >> +++ b/xen/arch/x86/domain.c >> @@ -692,6 +692,12 @@ int arch_sanitise_domain_config(struct xen_domctl_createdomain *config) >> return -EINVAL; >> } >> >> + if ( config->flags & XEN_DOMCTL_CDF_vpmu ) >> + { >> + dprintk(XENLOG_INFO, "vpmu support not ready yet\n"); >> + return -EINVAL; >> + } > > I consider this message potentially misleading (as x86 does have vPMU > support, it merely doesn't get enabled this way). But isn't this redundant > with ... > >> @@ -534,6 +535,12 @@ static int sanitise_domain_config(struct xen_domctl_createdomain *config) >> return -EINVAL; >> } >> >> + if ( vpmu && !vpmu_is_available ) >> + { >> + dprintk(XENLOG_INFO, "vpmu requested but not available\n"); >> + return -EINVAL; >> + } > > ... this? (This message is again potentially misleading.) > Ok. vpmu_is_available is false for x86 so the check in x86's arch_sanitise_domain_config is redundant. I will fix it. When it comes to the message itself "vpmu requested but not available". Does the following sound better for you? "vpmu requested but the platform does not support it" If not, can you please suggest a better message? >> --- a/xen/include/public/domctl.h >> +++ b/xen/include/public/domctl.h >> @@ -70,9 +70,12 @@ struct xen_domctl_createdomain { >> #define XEN_DOMCTL_CDF_iommu (1U<<_XEN_DOMCTL_CDF_iommu) >> #define _XEN_DOMCTL_CDF_nested_virt 6 >> #define XEN_DOMCTL_CDF_nested_virt (1U << _XEN_DOMCTL_CDF_nested_virt) >> +/* Should we expose the vPMU to the guest? */ >> +#define _XEN_DOMCTL_CDF_vpmu 7 >> +#define XEN_DOMCTL_CDF_vpmu (1U << _XEN_DOMCTL_CDF_vpmu) > > Like for the earlier patch, I think we should stop with the bad habit of > defining both the bit position and the mask separately. > Ok. I can change it. However there are lots of other places in Xen (e.g. asm-x86/hvm/irq.h) when such methodology is used. But I agree with you and I will change it. > Jan > Cheers, Michal
On 07.10.2021 10:21, Michal Orzel wrote: > Hi Jan, > > On 07.10.2021 10:03, Jan Beulich wrote: >> On 06.10.2021 12:58, Michal Orzel wrote: >>> --- a/xen/arch/x86/domain.c >>> +++ b/xen/arch/x86/domain.c >>> @@ -692,6 +692,12 @@ int arch_sanitise_domain_config(struct xen_domctl_createdomain *config) >>> return -EINVAL; >>> } >>> >>> + if ( config->flags & XEN_DOMCTL_CDF_vpmu ) >>> + { >>> + dprintk(XENLOG_INFO, "vpmu support not ready yet\n"); >>> + return -EINVAL; >>> + } >> >> I consider this message potentially misleading (as x86 does have vPMU >> support, it merely doesn't get enabled this way). But isn't this redundant >> with ... >> >>> @@ -534,6 +535,12 @@ static int sanitise_domain_config(struct xen_domctl_createdomain *config) >>> return -EINVAL; >>> } >>> >>> + if ( vpmu && !vpmu_is_available ) >>> + { >>> + dprintk(XENLOG_INFO, "vpmu requested but not available\n"); >>> + return -EINVAL; >>> + } >> >> ... this? (This message is again potentially misleading.) >> > Ok. vpmu_is_available is false for x86 so the check in x86's arch_sanitise_domain_config is redundant. > I will fix it. When it comes to the message itself "vpmu requested but not available". > Does the following sound better for you? > "vpmu requested but the platform does not support it" > If not, can you please suggest a better message? While it gets a little long then, appending "at domain creation time" would disambiguate the text. Or maybe "vPMU cannot be enabled this way"? It's a debug-only message after all, so its wording can quite well be developer- focused imo. Jan
diff --git a/docs/man/xl.cfg.5.pod.in b/docs/man/xl.cfg.5.pod.in index 4b1e3028d2..55c4881205 100644 --- a/docs/man/xl.cfg.5.pod.in +++ b/docs/man/xl.cfg.5.pod.in @@ -690,6 +690,23 @@ default. B<NOTE>: Acceptable values are platform specific. For Intel Processor Trace, this value must be a power of 2 between 4k and 16M. +=item B<vpmu=BOOLEAN> + +Currently ARM only. + +Specifies whether to enable the access to PMU registers by disabling +the PMU traps. + +The PMU registers are not virtualized and the physical registers are directly +accessible when this parameter is enabled. There is no interrupt support and +Xen will not save/restore the register values on context switches. + +vPMU, by design and purpose, exposes system level performance +information to the guest. Only to be used by sufficiently privileged +domains. This feature is currently in experimental state. + +If this option is not specified then it will default to B<false>. + =back =head2 Devices diff --git a/tools/golang/xenlight/helpers.gen.go b/tools/golang/xenlight/helpers.gen.go index c8669837d8..2449580bad 100644 --- a/tools/golang/xenlight/helpers.gen.go +++ b/tools/golang/xenlight/helpers.gen.go @@ -1119,6 +1119,9 @@ return fmt.Errorf("converting field ArchX86.MsrRelaxed: %v", err) } x.Altp2M = Altp2MMode(xc.altp2m) x.VmtraceBufKb = int(xc.vmtrace_buf_kb) +if err := x.Vpmu.fromC(&xc.vpmu);err != nil { +return fmt.Errorf("converting field Vpmu: %v", err) +} return nil} @@ -1600,6 +1603,9 @@ return fmt.Errorf("converting field ArchX86.MsrRelaxed: %v", err) } xc.altp2m = C.libxl_altp2m_mode(x.Altp2M) xc.vmtrace_buf_kb = C.int(x.VmtraceBufKb) +if err := x.Vpmu.toC(&xc.vpmu); err != nil { +return fmt.Errorf("converting field Vpmu: %v", err) +} return nil } diff --git a/tools/golang/xenlight/types.gen.go b/tools/golang/xenlight/types.gen.go index 45f2cba3d2..b2e8bd1a85 100644 --- a/tools/golang/xenlight/types.gen.go +++ b/tools/golang/xenlight/types.gen.go @@ -521,6 +521,7 @@ MsrRelaxed Defbool } Altp2M Altp2MMode VmtraceBufKb int +Vpmu Defbool } type DomainBuildInfoTypeUnion interface { diff --git a/tools/include/libxl.h b/tools/include/libxl.h index ec5e3badae..ee73eb06f1 100644 --- a/tools/include/libxl.h +++ b/tools/include/libxl.h @@ -508,6 +508,12 @@ */ #define LIBXL_HAVE_PHYSINFO_CAP_VPMU 1 +/* + * LIBXL_HAVE_VPMU indicates that libxl_domain_build_info has a vpmu parameter, + * which allows to enable the access to PMU registers. + */ +#define LIBXL_HAVE_VPMU 1 + /* * libxl ABI compatibility * diff --git a/tools/libs/light/libxl_create.c b/tools/libs/light/libxl_create.c index e356b2106d..d123c2f703 100644 --- a/tools/libs/light/libxl_create.c +++ b/tools/libs/light/libxl_create.c @@ -91,6 +91,7 @@ int libxl__domain_build_info_setdefault(libxl__gc *gc, } libxl_defbool_setdefault(&b_info->device_model_stubdomain, false); + libxl_defbool_setdefault(&b_info->vpmu, false); if (libxl_defbool_val(b_info->device_model_stubdomain) && !b_info->device_model_ssidref) @@ -622,6 +623,9 @@ int libxl__domain_make(libxl__gc *gc, libxl_domain_config *d_config, create.flags |= XEN_DOMCTL_CDF_nested_virt; } + if ( libxl_defbool_val(b_info->vpmu) ) + create.flags |= XEN_DOMCTL_CDF_vpmu; + assert(info->passthrough != LIBXL_PASSTHROUGH_DEFAULT); LOG(DETAIL, "passthrough: %s", libxl_passthrough_to_string(info->passthrough)); diff --git a/tools/libs/light/libxl_types.idl b/tools/libs/light/libxl_types.idl index 993e83acca..b96fb5c47e 100644 --- a/tools/libs/light/libxl_types.idl +++ b/tools/libs/light/libxl_types.idl @@ -655,6 +655,8 @@ libxl_domain_build_info = Struct("domain_build_info",[ # Use zero value to disable this feature. ("vmtrace_buf_kb", integer), + ("vpmu", libxl_defbool), + ], dir=DIR_IN, copy_deprecated_fn="libxl__domain_build_info_copy_deprecated", ) diff --git a/tools/ocaml/libs/xc/xenctrl.ml b/tools/ocaml/libs/xc/xenctrl.ml index 6da3ed3c6f..addcf4cc59 100644 --- a/tools/ocaml/libs/xc/xenctrl.ml +++ b/tools/ocaml/libs/xc/xenctrl.ml @@ -69,6 +69,7 @@ type domain_create_flag = | CDF_XS_DOMAIN | CDF_IOMMU | CDF_NESTED_VIRT + | CDF_VPMU type domain_create_iommu_opts = | IOMMU_NO_SHAREPT diff --git a/tools/ocaml/libs/xc/xenctrl.mli b/tools/ocaml/libs/xc/xenctrl.mli index b8faff6721..0a5ce529e9 100644 --- a/tools/ocaml/libs/xc/xenctrl.mli +++ b/tools/ocaml/libs/xc/xenctrl.mli @@ -62,6 +62,7 @@ type domain_create_flag = | CDF_XS_DOMAIN | CDF_IOMMU | CDF_NESTED_VIRT + | CDF_VPMU type domain_create_iommu_opts = | IOMMU_NO_SHAREPT diff --git a/tools/xl/xl_parse.c b/tools/xl/xl_parse.c index 17dddb4cd5..c503b9be00 100644 --- a/tools/xl/xl_parse.c +++ b/tools/xl/xl_parse.c @@ -2750,6 +2750,8 @@ skip_usbdev: "If it fixes an issue you are having please report to " "xen-devel@lists.xenproject.org.\n"); + xlu_cfg_get_defbool(config, "vpmu", &b_info->vpmu, 0); + xlu_cfg_destroy(config); } diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c index 19c756ac3d..2dd474da09 100644 --- a/xen/arch/arm/domain.c +++ b/xen/arch/arm/domain.c @@ -276,6 +276,8 @@ static void ctxt_switch_to(struct vcpu *n) * timer. The interrupt needs to be injected into the guest. */ WRITE_SYSREG(n->arch.cntkctl, CNTKCTL_EL1); virt_timer_restore(n); + + WRITE_SYSREG(n->arch.mdcr_el2, MDCR_EL2); } /* Update per-VCPU guest runstate shared memory area (if registered). */ @@ -586,6 +588,10 @@ int arch_vcpu_create(struct vcpu *v) v->arch.hcr_el2 = get_default_hcr_flags(); + v->arch.mdcr_el2 = HDCR_TDRA | HDCR_TDOSA | HDCR_TDA; + if ( !(v->domain->options & XEN_DOMCTL_CDF_vpmu) ) + v->arch.mdcr_el2 |= HDCR_TPM | HDCR_TPMCR; + if ( (rc = vcpu_vgic_init(v)) != 0 ) goto fail; @@ -622,8 +628,8 @@ int arch_sanitise_domain_config(struct xen_domctl_createdomain *config) { unsigned int max_vcpus; - /* HVM and HAP must be set. IOMMU may or may not be */ - if ( (config->flags & ~XEN_DOMCTL_CDF_iommu) != + /* HVM and HAP must be set. IOMMU and PMU may or may not be */ + if ( (config->flags & ~(XEN_DOMCTL_CDF_iommu | XEN_DOMCTL_CDF_vpmu)) != (XEN_DOMCTL_CDF_hvm | XEN_DOMCTL_CDF_hap) ) { dprintk(XENLOG_INFO, "Unsupported configuration %#x\n", diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c index 49dc90d198..85386a765a 100644 --- a/xen/arch/arm/setup.c +++ b/xen/arch/arm/setup.c @@ -108,6 +108,7 @@ static void __init processor_id(void) identify_cpu(c); current_cpu_data = *c; + vpmu_is_available = cpu_has_pmu; if ( c->midr.implementer < ARRAY_SIZE(processor_implementers) && processor_implementers[c->midr.implementer] ) diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c index ef1812dc14..406824a7a5 100644 --- a/xen/arch/x86/domain.c +++ b/xen/arch/x86/domain.c @@ -692,6 +692,12 @@ int arch_sanitise_domain_config(struct xen_domctl_createdomain *config) return -EINVAL; } + if ( config->flags & XEN_DOMCTL_CDF_vpmu ) + { + dprintk(XENLOG_INFO, "vpmu support not ready yet\n"); + return -EINVAL; + } + return 0; } diff --git a/xen/common/domain.c b/xen/common/domain.c index 4d0e909eec..37d8c55c69 100644 --- a/xen/common/domain.c +++ b/xen/common/domain.c @@ -480,12 +480,13 @@ static int sanitise_domain_config(struct xen_domctl_createdomain *config) bool hvm = config->flags & XEN_DOMCTL_CDF_hvm; bool hap = config->flags & XEN_DOMCTL_CDF_hap; bool iommu = config->flags & XEN_DOMCTL_CDF_iommu; + bool vpmu = config->flags & XEN_DOMCTL_CDF_vpmu; if ( config->flags & ~(XEN_DOMCTL_CDF_hvm | XEN_DOMCTL_CDF_hap | XEN_DOMCTL_CDF_s3_integrity | XEN_DOMCTL_CDF_oos_off | XEN_DOMCTL_CDF_xs_domain | XEN_DOMCTL_CDF_iommu | - XEN_DOMCTL_CDF_nested_virt) ) + XEN_DOMCTL_CDF_nested_virt | XEN_DOMCTL_CDF_vpmu) ) { dprintk(XENLOG_INFO, "Unknown CDF flags %#x\n", config->flags); return -EINVAL; @@ -534,6 +535,12 @@ static int sanitise_domain_config(struct xen_domctl_createdomain *config) return -EINVAL; } + if ( vpmu && !vpmu_is_available ) + { + dprintk(XENLOG_INFO, "vpmu requested but not available\n"); + return -EINVAL; + } + return arch_sanitise_domain_config(config); } diff --git a/xen/include/asm-arm/domain.h b/xen/include/asm-arm/domain.h index c9277b5c6d..14e575288f 100644 --- a/xen/include/asm-arm/domain.h +++ b/xen/include/asm-arm/domain.h @@ -166,6 +166,7 @@ struct arch_vcpu /* HYP configuration */ register_t hcr_el2; + register_t mdcr_el2; uint32_t teecr, teehbr; /* ThumbEE, 32-bit guests only */ #ifdef CONFIG_ARM_32 diff --git a/xen/include/public/domctl.h b/xen/include/public/domctl.h index 96696e3842..8f2a07cfe8 100644 --- a/xen/include/public/domctl.h +++ b/xen/include/public/domctl.h @@ -70,9 +70,12 @@ struct xen_domctl_createdomain { #define XEN_DOMCTL_CDF_iommu (1U<<_XEN_DOMCTL_CDF_iommu) #define _XEN_DOMCTL_CDF_nested_virt 6 #define XEN_DOMCTL_CDF_nested_virt (1U << _XEN_DOMCTL_CDF_nested_virt) +/* Should we expose the vPMU to the guest? */ +#define _XEN_DOMCTL_CDF_vpmu 7 +#define XEN_DOMCTL_CDF_vpmu (1U << _XEN_DOMCTL_CDF_vpmu) /* Max XEN_DOMCTL_CDF_* constant. Used for ABI checking. */ -#define XEN_DOMCTL_CDF_MAX XEN_DOMCTL_CDF_nested_virt +#define XEN_DOMCTL_CDF_MAX XEN_DOMCTL_CDF_vpmu uint32_t flags;