From: James Hogan <james.hogan@imgtec.com> To: Paolo Bonzini <pbonzini@redhat.com>, kvm@vger.kernel.org, linux-mips@linux-mips.org Cc: Ralf Baechle <ralf@linux-mips.org>, Gleb Natapov <gleb@kernel.org>, Jonathan Corbet <corbet@lwn.net>, linux-api@vger.kernel.org, linux-doc@vger.kernel.org Subject: Re: [PATCH 20/20] MIPS: KVM: Wire up MSA capability Date: Thu, 26 Mar 2015 14:52:59 +0000 [thread overview] Message-ID: <55141D4B.5000605@imgtec.com> (raw) In-Reply-To: <5514108F.9060905@redhat.com> [-- Attachment #1: Type: text/plain, Size: 4602 bytes --] On 26/03/15 13:58, Paolo Bonzini wrote: > > > On 11/03/2015 15:44, James Hogan wrote: >> Now that the code is in place for KVM to support MIPS SIMD Architecutre >> (MSA) in MIPS guests, wire up the new KVM_CAP_MIPS_MSA capability. >> >> For backwards compatibility, the capability must be explicitly enabled >> in order to detect or make use of MSA from the guest. >> >> The capability is not supported if the hardware supports MSA vector >> partitioning, since the extra support cannot be tested yet and it >> extends the state that the userland program would have to save. >> >> Signed-off-by: James Hogan <james.hogan@imgtec.com> >> Cc: Paolo Bonzini <pbonzini@redhat.com> >> Cc: Ralf Baechle <ralf@linux-mips.org> >> Cc: Gleb Natapov <gleb@kernel.org> >> Cc: Jonathan Corbet <corbet@lwn.net> >> Cc: linux-mips@linux-mips.org >> Cc: kvm@vger.kernel.org >> Cc: linux-api@vger.kernel.org >> Cc: linux-doc@vger.kernel.org >> Signed-off-by: James Hogan <james.hogan@imgtec.com> >> --- >> Documentation/virtual/kvm/api.txt | 12 ++++++++++++ >> arch/mips/kvm/mips.c | 24 ++++++++++++++++++++++++ >> include/uapi/linux/kvm.h | 1 + >> 3 files changed, 37 insertions(+) >> >> diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt >> index 47ddf0475211..97dd9ee69ca8 100644 >> --- a/Documentation/virtual/kvm/api.txt >> +++ b/Documentation/virtual/kvm/api.txt >> @@ -3224,6 +3224,18 @@ done the KVM_REG_MIPS_FPR_* and KVM_REG_MIPS_FCR_* registers can be accessed >> Config5.FRE bits are accessible via the KVM API and also from the guest, >> depending on them being supported by the FPU. >> >> +6.10 KVM_CAP_MIPS_MSA >> + >> +Architectures: mips >> +Target: vcpu >> +Parameters: args[0] is reserved for future use (should be 0). >> + >> +This capability allows the use of the MIPS SIMD Architecture (MSA) by the guest. >> +It allows the Config3.MSAP bit to be set to enable the use of MSA by the guest. >> +Once this is done the KVM_REG_MIPS_VEC_* and KVM_REG_MIPS_MSA_* registers can be >> +accessed, and the Config5.MSAEn bit is accessible via the KVM API and also from >> +the guest. >> + >> 7. Capabilities that can be enabled on VMs >> ------------------------------------------ >> >> diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c >> index 9319c4360285..3b3530f493eb 100644 >> --- a/arch/mips/kvm/mips.c >> +++ b/arch/mips/kvm/mips.c >> @@ -880,6 +880,15 @@ static int kvm_vcpu_ioctl_enable_cap(struct kvm_vcpu *vcpu, >> return -EINVAL; >> vcpu->arch.fpu_enabled = true; >> break; >> + case KVM_CAP_MIPS_MSA: >> + /* >> + * MSA vector partitioning not supported, >> + * see kvm_vm_ioctl_check_extension(). >> + */ >> + if (!cpu_has_msa || boot_cpu_data.msa_id & MSA_IR_WRPF) >> + return -EINVAL; > > Perhaps you can call kvm_vm_ioctl_check_extension directly, outside the > switch (it's okay if it's called for a capability other than FPU and MSA)? Yes, good idea. That works nicely. > > Apart from this nit, > > Acked-by: Paolo Bonzini <pbonzini@redhat.com> > > Paolo Thanks! James > >> + vcpu->arch.msa_enabled = true; >> + break; >> default: >> r = -EINVAL; >> break; >> @@ -1071,6 +1080,21 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) >> case KVM_CAP_MIPS_FPU: >> r = !!cpu_has_fpu; >> break; >> + case KVM_CAP_MIPS_MSA: >> + /* >> + * We don't support MSA vector partitioning yet: >> + * 1) It would require explicit support which can't be tested >> + * yet due to lack of support in current hardware. >> + * 2) It extends the state that would need to be saved/restored >> + * by e.g. QEMU for migration. >> + * >> + * When vector partitioning hardware becomes available, support >> + * could be added by requiring a flag when enabling >> + * KVM_CAP_MIPS_MSA capability to indicate that userland knows >> + * to save/restore the appropriate extra state. >> + */ >> + r = cpu_has_msa && !(boot_cpu_data.msa_id & MSA_IR_WRPF); >> + break; >> default: >> r = 0; >> break; >> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h >> index 98f6e5c653ff..5f859888e3ad 100644 >> --- a/include/uapi/linux/kvm.h >> +++ b/include/uapi/linux/kvm.h >> @@ -761,6 +761,7 @@ struct kvm_ppc_smmu_info { >> #define KVM_CAP_CHECK_EXTENSION_VM 105 >> #define KVM_CAP_S390_USER_SIGP 106 >> #define KVM_CAP_MIPS_FPU 107 >> +#define KVM_CAP_MIPS_MSA 108 >> >> #ifdef KVM_CAP_IRQ_ROUTING >> >> [-- Attachment #2: OpenPGP digital signature --] [-- Type: application/pgp-signature, Size: 819 bytes --]
WARNING: multiple messages have this Message-ID (diff)
From: James Hogan <james.hogan@imgtec.com> To: Paolo Bonzini <pbonzini@redhat.com>, <kvm@vger.kernel.org>, <linux-mips@linux-mips.org> Cc: Ralf Baechle <ralf@linux-mips.org>, Gleb Natapov <gleb@kernel.org>, Jonathan Corbet <corbet@lwn.net>, <linux-api@vger.kernel.org>, <linux-doc@vger.kernel.org> Subject: Re: [PATCH 20/20] MIPS: KVM: Wire up MSA capability Date: Thu, 26 Mar 2015 14:52:59 +0000 [thread overview] Message-ID: <55141D4B.5000605@imgtec.com> (raw) In-Reply-To: <5514108F.9060905@redhat.com> [-- Attachment #1: Type: text/plain, Size: 4602 bytes --] On 26/03/15 13:58, Paolo Bonzini wrote: > > > On 11/03/2015 15:44, James Hogan wrote: >> Now that the code is in place for KVM to support MIPS SIMD Architecutre >> (MSA) in MIPS guests, wire up the new KVM_CAP_MIPS_MSA capability. >> >> For backwards compatibility, the capability must be explicitly enabled >> in order to detect or make use of MSA from the guest. >> >> The capability is not supported if the hardware supports MSA vector >> partitioning, since the extra support cannot be tested yet and it >> extends the state that the userland program would have to save. >> >> Signed-off-by: James Hogan <james.hogan@imgtec.com> >> Cc: Paolo Bonzini <pbonzini@redhat.com> >> Cc: Ralf Baechle <ralf@linux-mips.org> >> Cc: Gleb Natapov <gleb@kernel.org> >> Cc: Jonathan Corbet <corbet@lwn.net> >> Cc: linux-mips@linux-mips.org >> Cc: kvm@vger.kernel.org >> Cc: linux-api@vger.kernel.org >> Cc: linux-doc@vger.kernel.org >> Signed-off-by: James Hogan <james.hogan@imgtec.com> >> --- >> Documentation/virtual/kvm/api.txt | 12 ++++++++++++ >> arch/mips/kvm/mips.c | 24 ++++++++++++++++++++++++ >> include/uapi/linux/kvm.h | 1 + >> 3 files changed, 37 insertions(+) >> >> diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt >> index 47ddf0475211..97dd9ee69ca8 100644 >> --- a/Documentation/virtual/kvm/api.txt >> +++ b/Documentation/virtual/kvm/api.txt >> @@ -3224,6 +3224,18 @@ done the KVM_REG_MIPS_FPR_* and KVM_REG_MIPS_FCR_* registers can be accessed >> Config5.FRE bits are accessible via the KVM API and also from the guest, >> depending on them being supported by the FPU. >> >> +6.10 KVM_CAP_MIPS_MSA >> + >> +Architectures: mips >> +Target: vcpu >> +Parameters: args[0] is reserved for future use (should be 0). >> + >> +This capability allows the use of the MIPS SIMD Architecture (MSA) by the guest. >> +It allows the Config3.MSAP bit to be set to enable the use of MSA by the guest. >> +Once this is done the KVM_REG_MIPS_VEC_* and KVM_REG_MIPS_MSA_* registers can be >> +accessed, and the Config5.MSAEn bit is accessible via the KVM API and also from >> +the guest. >> + >> 7. Capabilities that can be enabled on VMs >> ------------------------------------------ >> >> diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c >> index 9319c4360285..3b3530f493eb 100644 >> --- a/arch/mips/kvm/mips.c >> +++ b/arch/mips/kvm/mips.c >> @@ -880,6 +880,15 @@ static int kvm_vcpu_ioctl_enable_cap(struct kvm_vcpu *vcpu, >> return -EINVAL; >> vcpu->arch.fpu_enabled = true; >> break; >> + case KVM_CAP_MIPS_MSA: >> + /* >> + * MSA vector partitioning not supported, >> + * see kvm_vm_ioctl_check_extension(). >> + */ >> + if (!cpu_has_msa || boot_cpu_data.msa_id & MSA_IR_WRPF) >> + return -EINVAL; > > Perhaps you can call kvm_vm_ioctl_check_extension directly, outside the > switch (it's okay if it's called for a capability other than FPU and MSA)? Yes, good idea. That works nicely. > > Apart from this nit, > > Acked-by: Paolo Bonzini <pbonzini@redhat.com> > > Paolo Thanks! James > >> + vcpu->arch.msa_enabled = true; >> + break; >> default: >> r = -EINVAL; >> break; >> @@ -1071,6 +1080,21 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) >> case KVM_CAP_MIPS_FPU: >> r = !!cpu_has_fpu; >> break; >> + case KVM_CAP_MIPS_MSA: >> + /* >> + * We don't support MSA vector partitioning yet: >> + * 1) It would require explicit support which can't be tested >> + * yet due to lack of support in current hardware. >> + * 2) It extends the state that would need to be saved/restored >> + * by e.g. QEMU for migration. >> + * >> + * When vector partitioning hardware becomes available, support >> + * could be added by requiring a flag when enabling >> + * KVM_CAP_MIPS_MSA capability to indicate that userland knows >> + * to save/restore the appropriate extra state. >> + */ >> + r = cpu_has_msa && !(boot_cpu_data.msa_id & MSA_IR_WRPF); >> + break; >> default: >> r = 0; >> break; >> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h >> index 98f6e5c653ff..5f859888e3ad 100644 >> --- a/include/uapi/linux/kvm.h >> +++ b/include/uapi/linux/kvm.h >> @@ -761,6 +761,7 @@ struct kvm_ppc_smmu_info { >> #define KVM_CAP_CHECK_EXTENSION_VM 105 >> #define KVM_CAP_S390_USER_SIGP 106 >> #define KVM_CAP_MIPS_FPU 107 >> +#define KVM_CAP_MIPS_MSA 108 >> >> #ifdef KVM_CAP_IRQ_ROUTING >> >> [-- Attachment #2: OpenPGP digital signature --] [-- Type: application/pgp-signature, Size: 819 bytes --]
next prev parent reply other threads:[~2015-03-26 14:52 UTC|newest] Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-03-11 14:44 [PATCH 00/20] MIPS: KVM: Guest FPU & SIMD (MSA) support James Hogan 2015-03-11 14:44 ` James Hogan 2015-03-11 14:44 ` James Hogan 2015-03-11 14:44 ` James Hogan 2015-03-11 14:44 ` [PATCH 01/20] MIPS: KVM: Handle MSA Disabled exceptions from guest James Hogan 2015-03-11 14:44 ` James Hogan 2015-03-11 14:44 ` [PATCH 02/20] MIPS: Clear [MSA]FPE CSR.Cause after notify_die() James Hogan 2015-03-11 14:44 ` James Hogan 2015-03-23 13:56 ` Ralf Baechle 2015-04-08 0:43 ` Maciej W. Rozycki 2015-03-11 14:44 ` [PATCH 03/20] MIPS: KVM: Handle TRAP exceptions from guest kernel James Hogan 2015-03-11 14:44 ` James Hogan 2015-03-11 14:44 ` [PATCH 04/20] MIPS: KVM: Implement PRid CP0 register access James Hogan 2015-03-11 14:44 ` James Hogan 2015-03-11 14:44 ` [PATCH 05/20] MIPS: KVM: Sort kvm_mips_get_reg() registers James Hogan 2015-03-11 14:44 ` James Hogan 2015-03-11 14:44 ` [PATCH 06/20] MIPS: KVM: Drop pr_info messages on init/exit James Hogan 2015-03-11 14:44 ` James Hogan 2015-03-11 14:44 ` [PATCH 07/20] MIPS: KVM: Clean up register definitions a little James Hogan 2015-03-11 14:44 ` James Hogan 2015-03-11 14:44 ` [PATCH 08/20] MIPS: KVM: Simplify default guest Config registers James Hogan 2015-03-11 14:44 ` James Hogan 2015-03-11 14:44 ` [PATCH 09/20] MIPS: KVM: Add Config4/5 and writing of " James Hogan 2015-03-11 14:44 ` James Hogan 2015-03-11 14:44 ` [PATCH 10/20] MIPS: KVM: Add vcpu_get_regs/vcpu_set_regs callback James Hogan 2015-03-11 14:44 ` James Hogan 2015-03-11 14:44 ` [PATCH 11/20] MIPS: KVM: Add base guest FPU support James Hogan 2015-03-11 14:44 ` James Hogan 2015-03-11 14:44 ` [PATCH 12/20] MIPS: KVM: Emulate FPU bits in COP0 interface James Hogan 2015-03-11 14:44 ` James Hogan 2015-03-11 14:44 ` [PATCH 13/20] MIPS: KVM: Add FP exception handling James Hogan 2015-03-11 14:44 ` James Hogan 2015-03-11 14:44 ` [PATCH 14/20] MIPS: KVM: Expose FPU registers James Hogan 2015-03-11 14:44 ` James Hogan 2015-03-26 13:55 ` Paolo Bonzini 2015-03-11 14:44 ` [PATCH 16/20] MIPS: KVM: Add base guest MSA support James Hogan 2015-03-11 14:44 ` James Hogan 2015-03-11 14:44 ` [PATCH 17/20] MIPS: KVM: Emulate MSA bits in COP0 interface James Hogan 2015-03-11 14:44 ` James Hogan 2015-03-11 14:44 ` [PATCH 18/20] MIPS: KVM: Add MSA exception handling James Hogan 2015-03-11 14:44 ` James Hogan [not found] ` <1426085096-12932-1-git-send-email-james.hogan-1AXoQHu6uovQT0dZR+AlfA@public.gmane.org> 2015-03-11 14:44 ` [PATCH 15/20] MIPS: KVM: Wire up FPU capability James Hogan 2015-03-11 14:44 ` James Hogan 2015-03-11 14:44 ` James Hogan 2015-03-11 14:44 ` James Hogan 2015-03-11 14:44 ` [PATCH 19/20] MIPS: KVM: Expose MSA registers James Hogan 2015-03-11 14:44 ` James Hogan 2015-03-11 14:44 ` James Hogan 2015-03-11 14:44 ` James Hogan 2015-03-11 14:44 ` [PATCH 20/20] MIPS: KVM: Wire up MSA capability James Hogan 2015-03-11 14:44 ` James Hogan 2015-03-26 13:58 ` Paolo Bonzini 2015-03-26 14:52 ` James Hogan [this message] 2015-03-26 14:52 ` James Hogan
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