| Message ID | 1610425048-990-1-git-send-email-igor.druzhinin@citrix.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2,1/2] viridian: remove implicit limit of 64 VPs per partition | expand |
On 12/01/2021 04:17, Igor Druzhinin wrote: > TLFS 7.8.1 stipulates that "a virtual processor index must be less than > the maximum number of virtual processors per partition" that "can be obtained > through CPUID leaf 0x40000005". Furthermore, "Requirements for Implementing > the Microsoft Hypervisor Interface" defines that starting from Windows Server > 2012, which allowed more than 64 CPUs to be brought up, this leaf can now > contain a value -1 basically assuming the hypervisor has no restriction while > 0 (that we currently expose) means the default restriction is still present. > > Along with the previous changes exposing ExProcessorMasks this allows a recent > Windows VM with Viridian extension enabled to have more than 64 vCPUs without > going into BSOD in some cases. > > Since we didn't expose the leaf before and to keep CPUID data consistent for > incoming streams from previous Xen versions - let's keep it behind an option. > > Signed-off-by: Igor Druzhinin <igor.druzhinin@citrix.com> > --- ping? Paul? Igor
On 25.01.2021 16:37, Igor Druzhinin wrote: > On 12/01/2021 04:17, Igor Druzhinin wrote: >> TLFS 7.8.1 stipulates that "a virtual processor index must be less than >> the maximum number of virtual processors per partition" that "can be obtained >> through CPUID leaf 0x40000005". Furthermore, "Requirements for Implementing >> the Microsoft Hypervisor Interface" defines that starting from Windows Server >> 2012, which allowed more than 64 CPUs to be brought up, this leaf can now >> contain a value -1 basically assuming the hypervisor has no restriction while >> 0 (that we currently expose) means the default restriction is still present. >> >> Along with the previous changes exposing ExProcessorMasks this allows a recent >> Windows VM with Viridian extension enabled to have more than 64 vCPUs without >> going into BSOD in some cases. >> >> Since we didn't expose the leaf before and to keep CPUID data consistent for >> incoming streams from previous Xen versions - let's keep it behind an option. >> >> Signed-off-by: Igor Druzhinin <igor.druzhinin@citrix.com> >> --- > > ping? Paul? Paul - I saw a reply by you on patch 2, but not on this one. libxl maintainers - both patches would want to be acked by you. Jan
> -----Original Message----- > From: Igor Druzhinin <igor.druzhinin@citrix.com> > Sent: 12 January 2021 04:17 > To: xen-devel@lists.xenproject.org > Cc: iwj@xenproject.org; wl@xen.org; andrew.cooper3@citrix.com; george.dunlap@citrix.com; > jbeulich@suse.com; julien@xen.org; sstabellini@kernel.org; anthony.perard@citrix.com; paul@xen.org; > roger.pau@citrix.com; Igor Druzhinin <igor.druzhinin@citrix.com> > Subject: [PATCH v2 1/2] viridian: remove implicit limit of 64 VPs per partition > > TLFS 7.8.1 stipulates that "a virtual processor index must be less than > the maximum number of virtual processors per partition" that "can be obtained > through CPUID leaf 0x40000005". Furthermore, "Requirements for Implementing > the Microsoft Hypervisor Interface" defines that starting from Windows Server > 2012, which allowed more than 64 CPUs to be brought up, this leaf can now > contain a value -1 basically assuming the hypervisor has no restriction while > 0 (that we currently expose) means the default restriction is still present. > > Along with the previous changes exposing ExProcessorMasks this allows a recent > Windows VM with Viridian extension enabled to have more than 64 vCPUs without > going into BSOD in some cases. > > Since we didn't expose the leaf before and to keep CPUID data consistent for > incoming streams from previous Xen versions - let's keep it behind an option. > > Signed-off-by: Igor Druzhinin <igor.druzhinin@citrix.com> Reviewed-by: Paul Durrant <paul@xen.org>
> -----Original Message----- > From: Jan Beulich <jbeulich@suse.com> > Sent: 29 January 2021 10:31 > To: paul@xen.org; iwj@xenproject.org; wl@xen.org; anthony.perard@citrix.com > Cc: andrew.cooper3@citrix.com; george.dunlap@citrix.com; julien@xen.org; sstabellini@kernel.org; > roger.pau@citrix.com; xen-devel@lists.xenproject.org; Igor Druzhinin <igor.druzhinin@citrix.com> > Subject: Ping: [PATCH v2 1/2] viridian: remove implicit limit of 64 VPs per partition > > On 25.01.2021 16:37, Igor Druzhinin wrote: > > On 12/01/2021 04:17, Igor Druzhinin wrote: > >> TLFS 7.8.1 stipulates that "a virtual processor index must be less than > >> the maximum number of virtual processors per partition" that "can be obtained > >> through CPUID leaf 0x40000005". Furthermore, "Requirements for Implementing > >> the Microsoft Hypervisor Interface" defines that starting from Windows Server > >> 2012, which allowed more than 64 CPUs to be brought up, this leaf can now > >> contain a value -1 basically assuming the hypervisor has no restriction while > >> 0 (that we currently expose) means the default restriction is still present. > >> > >> Along with the previous changes exposing ExProcessorMasks this allows a recent > >> Windows VM with Viridian extension enabled to have more than 64 vCPUs without > >> going into BSOD in some cases. > >> > >> Since we didn't expose the leaf before and to keep CPUID data consistent for > >> incoming streams from previous Xen versions - let's keep it behind an option. > >> > >> Signed-off-by: Igor Druzhinin <igor.druzhinin@citrix.com> > >> --- > > > > ping? Paul? > > Paul - I saw a reply by you on patch 2, but not on this one. > Oh sorry, yes. Done now. Paul > libxl maintainers - both patches would want to be acked by you. > > Jan
On Tue, Jan 12, 2021 at 04:17:27AM +0000, Igor Druzhinin wrote: > TLFS 7.8.1 stipulates that "a virtual processor index must be less than > the maximum number of virtual processors per partition" that "can be obtained > through CPUID leaf 0x40000005". Furthermore, "Requirements for Implementing > the Microsoft Hypervisor Interface" defines that starting from Windows Server > 2012, which allowed more than 64 CPUs to be brought up, this leaf can now > contain a value -1 basically assuming the hypervisor has no restriction while > 0 (that we currently expose) means the default restriction is still present. > > Along with the previous changes exposing ExProcessorMasks this allows a recent > Windows VM with Viridian extension enabled to have more than 64 vCPUs without > going into BSOD in some cases. > > Since we didn't expose the leaf before and to keep CPUID data consistent for > incoming streams from previous Xen versions - let's keep it behind an option. > > Signed-off-by: Igor Druzhinin <igor.druzhinin@citrix.com> Acked-by: Anthony PERARD <anthony.perard@citrix.com> Thanks,
diff --git a/docs/man/xl.cfg.5.pod.in b/docs/man/xl.cfg.5.pod.in index c8e017f..3467eae 100644 --- a/docs/man/xl.cfg.5.pod.in +++ b/docs/man/xl.cfg.5.pod.in @@ -2260,11 +2260,18 @@ mask. Hence this enlightenment must be specified for guests with more than 64 vCPUs if B<hcall_remote_tlb_flush> and/or B<hcall_ipi> are also specified. +=item B<no_vp_limit> + +This group when set indicates to a guest that the hypervisor does not +explicitly have any limits on the number of Virtual processors a guest +is allowed to bring up. It is strongly recommended to keep this enabled +for guests with more than 64 vCPUs. + =item B<defaults> This is a special value that enables the default set of groups, which is currently the B<base>, B<freq>, B<time_ref_count>, B<apic_assist>, -B<crash_ctl> and B<stimer> groups. +B<crash_ctl>, B<stimer> and B<no_vp_limit> groups. =item B<all> diff --git a/tools/include/libxl.h b/tools/include/libxl.h index 3433c95..be1e288 100644 --- a/tools/include/libxl.h +++ b/tools/include/libxl.h @@ -452,6 +452,12 @@ #define LIBXL_HAVE_VIRIDIAN_EX_PROCESSOR_MASKS 1 /* + * LIBXL_HAVE_VIRIDIAN_NO_VP_LIMIT indicates that the 'no_vp_limit' value + * is present in the viridian enlightenment enumeration. + */ +#define LIBXL_HAVE_VIRIDIAN_NO_VP_LIMIT 1 + +/* * LIBXL_HAVE_DEVICE_PCI_LIST_FREE indicates that the * libxl_device_pci_list_free() function is defined. */ diff --git a/tools/libs/light/libxl_types.idl b/tools/libs/light/libxl_types.idl index 0532473..8502b29 100644 --- a/tools/libs/light/libxl_types.idl +++ b/tools/libs/light/libxl_types.idl @@ -239,6 +239,7 @@ libxl_viridian_enlightenment = Enumeration("viridian_enlightenment", [ (8, "stimer"), (9, "hcall_ipi"), (10, "ex_processor_masks"), + (11, "no_vp_limit"), ]) libxl_hdtype = Enumeration("hdtype", [ diff --git a/tools/libs/light/libxl_x86.c b/tools/libs/light/libxl_x86.c index 86d2729..5c4c194 100644 --- a/tools/libs/light/libxl_x86.c +++ b/tools/libs/light/libxl_x86.c @@ -309,6 +309,7 @@ static int hvm_set_viridian_features(libxl__gc *gc, uint32_t domid, libxl_bitmap_set(&enlightenments, LIBXL_VIRIDIAN_ENLIGHTENMENT_TIME_REF_COUNT); libxl_bitmap_set(&enlightenments, LIBXL_VIRIDIAN_ENLIGHTENMENT_APIC_ASSIST); libxl_bitmap_set(&enlightenments, LIBXL_VIRIDIAN_ENLIGHTENMENT_CRASH_CTL); + libxl_bitmap_set(&enlightenments, LIBXL_VIRIDIAN_ENLIGHTENMENT_NO_VP_LIMIT); } libxl_for_each_set_bit(v, info->u.hvm.viridian_enable) { @@ -369,6 +370,9 @@ static int hvm_set_viridian_features(libxl__gc *gc, uint32_t domid, if (libxl_bitmap_test(&enlightenments, LIBXL_VIRIDIAN_ENLIGHTENMENT_EX_PROCESSOR_MASKS)) mask |= HVMPV_ex_processor_masks; + if (libxl_bitmap_test(&enlightenments, LIBXL_VIRIDIAN_ENLIGHTENMENT_NO_VP_LIMIT)) + mask |= HVMPV_no_vp_limit; + if (mask != 0 && xc_hvm_param_set(CTX->xch, domid, diff --git a/xen/arch/x86/hvm/viridian/viridian.c b/xen/arch/x86/hvm/viridian/viridian.c index ed97804..ae1ea86 100644 --- a/xen/arch/x86/hvm/viridian/viridian.c +++ b/xen/arch/x86/hvm/viridian/viridian.c @@ -209,6 +209,29 @@ void cpuid_viridian_leaves(const struct vcpu *v, uint32_t leaf, res->b = viridian_spinlock_retry_count; break; + case 5: + /* + * From "Requirements for Implementing the Microsoft Hypervisor + * Interface": + * + * "On Windows operating systems versions through Windows Server + * 2008 R2, reporting the HV#1 hypervisor interface limits + * the Windows virtual machine to a maximum of 64 VPs, regardless of + * what is reported via CPUID.40000005.EAX. + * + * Starting with Windows Server 2012 and Windows 8, if + * CPUID.40000005.EAX containsa value of -1, Windows assumes that + * the hypervisor imposes no specific limit to the number of VPs. + * In this case, Windows Server 2012 guest VMs may use more than 64 + * VPs, up to the maximum supported number of processors applicable + * to the specific Windows version being used." + * + * For compatibility we hide it behind an option. + */ + if ( viridian_feature_mask(d) & HVMPV_no_vp_limit ) + res->a = -1; + break; + case 6: /* Detected and in use hardware features. */ if ( cpu_has_vmx_virtualize_apic_accesses ) diff --git a/xen/include/public/hvm/params.h b/xen/include/public/hvm/params.h index 3b0a0f4..805f4ca 100644 --- a/xen/include/public/hvm/params.h +++ b/xen/include/public/hvm/params.h @@ -168,6 +168,10 @@ #define _HVMPV_ex_processor_masks 10 #define HVMPV_ex_processor_masks (1 << _HVMPV_ex_processor_masks) +/* Allow more than 64 VPs */ +#define _HVMPV_no_vp_limit 11 +#define HVMPV_no_vp_limit (1 << _HVMPV_no_vp_limit) + #define HVMPV_feature_mask \ (HVMPV_base_freq | \ HVMPV_no_freq | \ @@ -179,7 +183,8 @@ HVMPV_synic | \ HVMPV_stimer | \ HVMPV_hcall_ipi | \ - HVMPV_ex_processor_masks) + HVMPV_ex_processor_masks | \ + HVMPV_no_vp_limit) #endif
TLFS 7.8.1 stipulates that "a virtual processor index must be less than the maximum number of virtual processors per partition" that "can be obtained through CPUID leaf 0x40000005". Furthermore, "Requirements for Implementing the Microsoft Hypervisor Interface" defines that starting from Windows Server 2012, which allowed more than 64 CPUs to be brought up, this leaf can now contain a value -1 basically assuming the hypervisor has no restriction while 0 (that we currently expose) means the default restriction is still present. Along with the previous changes exposing ExProcessorMasks this allows a recent Windows VM with Viridian extension enabled to have more than 64 vCPUs without going into BSOD in some cases. Since we didn't expose the leaf before and to keep CPUID data consistent for incoming streams from previous Xen versions - let's keep it behind an option. Signed-off-by: Igor Druzhinin <igor.druzhinin@citrix.com> --- Changes in v2: - expose the option in libxl --- docs/man/xl.cfg.5.pod.in | 9 ++++++++- tools/include/libxl.h | 6 ++++++ tools/libs/light/libxl_types.idl | 1 + tools/libs/light/libxl_x86.c | 4 ++++ xen/arch/x86/hvm/viridian/viridian.c | 23 +++++++++++++++++++++++ xen/include/public/hvm/params.h | 7 ++++++- 6 files changed, 48 insertions(+), 2 deletions(-)