From: Alexander Graf <agraf@suse.de>
To: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
kvm-ppc@vger.kernel.org, kvm@vger.kernel.org
Subject: Re: [PATCH 19/23] KVM: PPC: Book3S: Select PR vs HV separately for each guest
Date: Thu, 12 Sep 2013 17:56:11 -0500 [thread overview]
Message-ID: <2E17A7F9-C96F-4372-91D1-18D1753EFB32@suse.de> (raw)
In-Reply-To: <20130806042628.GY19254@iris.ozlabs.ibm.com>
On 05.08.2013, at 23:26, Paul Mackerras wrote:
> This makes it possible to have both PR and HV guests running
> concurrently on one machine, by deferring the decision about which type
> of KVM to use for each guest until it either enables the PAPR capability
> or runs a vcpu. (Of course, this is only possible if both
> CONFIG_KVM_BOOK3S_PR and CONFIG_KVM_BOOK3S_64_HV are enabled.)
>
> Guests start out essentially as PR guests but with kvm->arch.kvm_mode
> set to KVM_MODE_UNKNOWN. If the guest then enables the KVM_CAP_PPC_PAPR
> capability, and the machine is capable of running HV guests (i.e. it
> has suitable CPUs and has a usable hypervisor mode available), the
> guest gets converted to an HV guest at that point. If userspace runs
> a vcpu without having enabled the KVM_CAP_PPC_PAPR capability, the
> guest is confirmed as a PR guest at that point.
>
> This also moves the preloading of the FPU for PR guests from
> kvmppc_set_msr_pr() into kvmppc_handle_exit_pr(), because
> kvmppc_set_msr_pr() can be called before any vcpu has been run, and
> it may be that the guest will end up as a HV guest, and in this case
> the preloading is not appropriate. Instead it is now done after we
> have emulated a privileged or illegal instruction, if the guest MSR
> now has FP set.
>
> Signed-off-by: Paul Mackerras <paulus@samba.org>
We need to have a way to force set the mode to either HV, PR or "try HV, fall back to PR if it wouldn't work" (the one you implemented). That way management software can choose to not default to fallback mode if it wants to guarantee consistent performance.
Alex
WARNING: multiple messages have this Message-ID (diff)
From: Alexander Graf <agraf@suse.de>
To: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
kvm-ppc@vger.kernel.org, kvm@vger.kernel.org
Subject: Re: [PATCH 19/23] KVM: PPC: Book3S: Select PR vs HV separately for each guest
Date: Thu, 12 Sep 2013 22:56:11 +0000 [thread overview]
Message-ID: <2E17A7F9-C96F-4372-91D1-18D1753EFB32@suse.de> (raw)
In-Reply-To: <20130806042628.GY19254@iris.ozlabs.ibm.com>
On 05.08.2013, at 23:26, Paul Mackerras wrote:
> This makes it possible to have both PR and HV guests running
> concurrently on one machine, by deferring the decision about which type
> of KVM to use for each guest until it either enables the PAPR capability
> or runs a vcpu. (Of course, this is only possible if both
> CONFIG_KVM_BOOK3S_PR and CONFIG_KVM_BOOK3S_64_HV are enabled.)
>
> Guests start out essentially as PR guests but with kvm->arch.kvm_mode
> set to KVM_MODE_UNKNOWN. If the guest then enables the KVM_CAP_PPC_PAPR
> capability, and the machine is capable of running HV guests (i.e. it
> has suitable CPUs and has a usable hypervisor mode available), the
> guest gets converted to an HV guest at that point. If userspace runs
> a vcpu without having enabled the KVM_CAP_PPC_PAPR capability, the
> guest is confirmed as a PR guest at that point.
>
> This also moves the preloading of the FPU for PR guests from
> kvmppc_set_msr_pr() into kvmppc_handle_exit_pr(), because
> kvmppc_set_msr_pr() can be called before any vcpu has been run, and
> it may be that the guest will end up as a HV guest, and in this case
> the preloading is not appropriate. Instead it is now done after we
> have emulated a privileged or illegal instruction, if the guest MSR
> now has FP set.
>
> Signed-off-by: Paul Mackerras <paulus@samba.org>
We need to have a way to force set the mode to either HV, PR or "try HV, fall back to PR if it wouldn't work" (the one you implemented). That way management software can choose to not default to fallback mode if it wants to guarantee consistent performance.
Alex
next prev parent reply other threads:[~2013-09-12 22:56 UTC|newest]
Thread overview: 136+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-06 4:12 [PATCH 00/23] Allow PR and HV KVM to coexist in one kernel Paul Mackerras
2013-08-06 4:12 ` Paul Mackerras
2013-08-06 4:13 ` [PATCH 01/23] KVM: PPC: Book3S: Fix compile error in XICS emulation Paul Mackerras
2013-08-06 4:13 ` Paul Mackerras
2013-08-28 22:51 ` Alexander Graf
2013-08-28 22:51 ` Alexander Graf
2013-08-06 4:14 ` [PATCH 02/23] KVM: PPC: Book3S PR: Don't corrupt guest state when kernel uses VMX Paul Mackerras
2013-08-06 4:14 ` Paul Mackerras
2013-08-08 15:49 ` Aneesh Kumar K.V
2013-08-08 15:49 ` Aneesh Kumar K.V
2013-08-28 22:51 ` Alexander Graf
2013-08-28 22:51 ` Alexander Graf
2013-08-06 4:15 ` [PATCH 03/23] KVM: PPC: Book3S PR: Make instruction fetch fallback work for system calls Paul Mackerras
2013-08-06 4:15 ` Paul Mackerras
2013-08-28 22:51 ` Alexander Graf
2013-08-28 22:51 ` Alexander Graf
2013-08-06 4:16 ` [PATCH 04/23] KVM: PPC: Book3S PR: Keep volatile reg values in vcpu rather than shadow_vcpu Paul Mackerras
2013-08-06 4:16 ` Paul Mackerras
2013-08-11 11:06 ` Aneesh Kumar K.V
2013-08-11 11:18 ` Aneesh Kumar K.V
2013-08-28 22:00 ` Alexander Graf
2013-08-28 22:00 ` Alexander Graf
2013-08-29 5:04 ` Paul Mackerras
2013-08-29 5:04 ` Paul Mackerras
2013-08-29 12:46 ` Alexander Graf
2013-08-29 12:46 ` Alexander Graf
2013-08-06 4:18 ` [PATCH 05/23] KVM: PPC: Book3S PR: Rework kvmppc_mmu_book3s_64_xlate() Paul Mackerras
2013-08-06 4:18 ` Paul Mackerras
2013-08-28 22:51 ` Alexander Graf
2013-08-28 22:51 ` Alexander Graf
2013-08-06 4:18 ` [PATCH 06/23] KVM: PPC: Book3S PR: Allow guest to use 64k pages Paul Mackerras
2013-08-06 4:18 ` Paul Mackerras
2013-08-28 22:56 ` Alexander Graf
2013-08-28 22:56 ` Alexander Graf
2013-08-29 5:17 ` Paul Mackerras
2013-08-29 5:17 ` Paul Mackerras
2013-08-29 12:48 ` Alexander Graf
2013-08-29 12:48 ` Alexander Graf
2013-08-06 4:19 ` [PATCH 07/23] KVM: PPC: Book3S PR: Use 64k host pages where possible Paul Mackerras
2013-08-06 4:19 ` Paul Mackerras
2013-08-28 23:24 ` Alexander Graf
2013-08-28 23:24 ` Alexander Graf
2013-08-29 5:23 ` Paul Mackerras
2013-08-29 5:23 ` Paul Mackerras
2013-08-29 12:43 ` Alexander Graf
2013-08-29 12:43 ` Alexander Graf
2013-08-06 4:20 ` [PATCH 08/23] KVM: PPC: Book3S PR: Handle PP0 page-protection bit in guest HPTEs Paul Mackerras
2013-08-06 4:20 ` Paul Mackerras
2013-08-06 4:20 ` [PATCH 09/23] KVM: PPC: Book3S PR: Correct errors in H_ENTER implementation Paul Mackerras
2013-08-06 4:20 ` Paul Mackerras
2013-08-06 4:21 ` [PATCH 10/23] KVM: PPC: Book3S PR: Make HPT accesses and updates SMP-safe Paul Mackerras
2013-08-06 4:21 ` Paul Mackerras
2013-08-06 4:21 ` [PATCH 11/23] KVM: PPC: Book3S PR: Allocate kvm_vcpu structs from kvm_vcpu_cache Paul Mackerras
2013-08-06 4:21 ` Paul Mackerras
2013-08-12 10:03 ` Aneesh Kumar K.V
2013-08-12 10:15 ` Aneesh Kumar K.V
2013-08-06 4:22 ` [PATCH 12/23] KVM: PPC: Book3S HV: Better handling of exceptions that happen in real mode Paul Mackerras
2013-08-06 4:22 ` Paul Mackerras
2013-08-06 4:22 ` [PATCH 13/23] KVM: PPC: Book3S: Move skip-interrupt handlers to common code Paul Mackerras
2013-08-06 4:22 ` Paul Mackerras
2013-08-06 4:23 ` [PATCH 14/23] KVM: PPC: Book3S PR: Delay disabling relocation-on interrupts Paul Mackerras
2013-08-06 4:23 ` Paul Mackerras
2013-08-30 16:30 ` Alexander Graf
2013-08-30 16:30 ` Alexander Graf
2013-08-30 22:55 ` Paul Mackerras
2013-08-30 22:55 ` Paul Mackerras
2013-08-30 23:13 ` Alexander Graf
2013-08-30 23:13 ` Alexander Graf
2013-08-31 5:42 ` Paul Mackerras
2013-08-31 5:42 ` Paul Mackerras
2013-08-06 4:24 ` [PATCH 15/23] KVM: PPC: Book3S: Rename symbols that exist in both PR and HV KVM Paul Mackerras
2013-08-06 4:24 ` Paul Mackerras
2013-08-06 4:24 ` [PATCH 16/23] KVM: PPC: Book3S: Merge implementations of KVM_PPC_GET_SMMU_INFO ioctl Paul Mackerras
2013-08-06 4:24 ` Paul Mackerras
2013-08-06 4:25 ` [PATCH 17/23] KVM: PPC: Book3S HV: Factorize kvmppc_core_vcpu_create_hv() Paul Mackerras
2013-08-06 4:25 ` Paul Mackerras
2013-08-06 4:25 ` [PATCH 18/23] KVM: PPC: Book3S: Allow both PR and HV KVM to be selected Paul Mackerras
2013-08-06 4:25 ` Paul Mackerras
2013-08-06 4:26 ` [PATCH 19/23] KVM: PPC: Book3S: Select PR vs HV separately for each guest Paul Mackerras
2013-08-06 4:26 ` Paul Mackerras
2013-09-12 22:56 ` Alexander Graf [this message]
2013-09-12 22:56 ` Alexander Graf
2013-09-13 0:17 ` Paul Mackerras
2013-09-13 0:17 ` Paul Mackerras
2013-09-13 1:31 ` Benjamin Herrenschmidt
2013-09-13 1:31 ` Benjamin Herrenschmidt
2013-09-13 4:18 ` Alexander Graf
2013-09-13 4:18 ` Alexander Graf
2013-09-14 18:33 ` Aneesh Kumar K.V
2013-09-14 18:45 ` Aneesh Kumar K.V
2013-09-14 20:22 ` Alexander Graf
2013-09-14 20:22 ` Alexander Graf
2013-09-15 9:16 ` Aneesh Kumar K.V
2013-09-15 9:28 ` Aneesh Kumar K.V
2013-09-15 11:55 ` Alexander Graf
2013-09-15 11:55 ` Alexander Graf
2013-09-13 4:17 ` Alexander Graf
2013-09-13 4:17 ` Alexander Graf
2013-09-18 12:05 ` Paul Mackerras
2013-09-18 12:05 ` Paul Mackerras
2013-09-19 7:31 ` Alexander Graf
2013-09-19 7:31 ` Alexander Graf
2013-08-06 4:27 ` [PATCH 20/23] KVM: PPC: Book3S PR: Better handling of host-side read-only pages Paul Mackerras
2013-08-06 4:27 ` Paul Mackerras
2013-09-12 23:01 ` Alexander Graf
2013-09-12 23:01 ` Alexander Graf
2013-09-13 0:23 ` Paul Mackerras
2013-09-13 0:23 ` Paul Mackerras
2013-09-14 5:24 ` Paul Mackerras
2013-09-14 5:24 ` Paul Mackerras
2013-09-14 20:23 ` Alexander Graf
2013-09-14 20:23 ` Alexander Graf
2013-09-16 4:12 ` Paul Mackerras
2013-09-16 4:12 ` Paul Mackerras
2013-09-16 12:47 ` Alexander Graf
2013-09-16 12:47 ` Alexander Graf
2013-08-06 4:27 ` [PATCH 21/23] KVM: PPC: Book3S PR: Use mmu_notifier_retry() in kvmppc_mmu_map_page() Paul Mackerras
2013-08-06 4:27 ` Paul Mackerras
2013-08-07 4:13 ` Bhushan Bharat-R65777
2013-08-07 4:13 ` Bhushan Bharat-R65777
2013-08-07 4:28 ` Paul Mackerras
2013-08-07 4:28 ` Paul Mackerras
2013-08-07 5:18 ` Bhushan Bharat-R65777
2013-08-07 5:18 ` Bhushan Bharat-R65777
2013-08-07 5:17 ` Bhushan Bharat-R65777
2013-08-07 5:17 ` Bhushan Bharat-R65777
2013-08-07 8:27 ` Paul Mackerras
2013-08-07 8:27 ` Paul Mackerras
2013-08-07 8:31 ` Bhushan Bharat-R65777
2013-08-07 8:31 ` Bhushan Bharat-R65777
2013-08-08 12:06 ` Paul Mackerras
2013-08-08 12:06 ` Paul Mackerras
2013-08-06 4:27 ` [PATCH 22/23] KVM: PPC: Book3S PR: Mark pages accessed, and dirty if being written Paul Mackerras
2013-08-06 4:27 ` Paul Mackerras
2013-08-06 4:28 ` [PATCH 23/23] KVM: PPC: Book3S PR: Reduce number of shadow PTEs invalidated by MMU notifiers Paul Mackerras
2013-08-06 4:28 ` Paul Mackerras
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