From: Peter Zijlstra <peterz@infradead.org> To: Josh Poimboeuf <jpoimboe@redhat.com> Cc: "Jürgen Groß" <jgross@suse.com>, xen-devel@lists.xenproject.org, x86@kernel.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-hyperv@vger.kernel.org, kvm@vger.kernel.org, luto@kernel.org, "Thomas Gleixner" <tglx@linutronix.de>, "Ingo Molnar" <mingo@redhat.com>, "Borislav Petkov" <bp@alien8.de>, "H. Peter Anvin" <hpa@zytor.com>, "Boris Ostrovsky" <boris.ostrovsky@oracle.com>, "Stefano Stabellini" <sstabellini@kernel.org>, "Deep Shah" <sdeep@vmware.com>, "VMware, Inc." <pv-drivers@vmware.com>, "K. Y. Srinivasan" <kys@microsoft.com>, "Haiyang Zhang" <haiyangz@microsoft.com>, "Stephen Hemminger" <sthemmin@microsoft.com>, "Wei Liu" <wei.liu@kernel.org>, "Paolo Bonzini" <pbonzini@redhat.com>, "Sean Christopherson" <sean.j.christopherson@intel.com>, "Vitaly Kuznetsov" <vkuznets@redhat.com>, "Wanpeng Li" <wanpengli@tencent.com>, "Jim Mattson" <jmattson@google.com>, "Joerg Roedel" <joro@8bytes.org>, "Daniel Lezcano" <daniel.lezcano@linaro.org>, "Juri Lelli" <juri.lelli@redhat.com>, "Vincent Guittot" <vincent.guittot@linaro.org>, "Dietmar Eggemann" <dietmar.eggemann@arm.com>, "Steven Rostedt" <rostedt@goodmis.org>, "Ben Segall" <bsegall@google.com>, "Mel Gorman" <mgorman@suse.de>, "Daniel Bristot de Oliveira" <bristot@redhat.com> Subject: Re: [PATCH v2 00/12] x86: major paravirt cleanup Date: Wed, 16 Dec 2020 18:58:28 +0100 [thread overview] Message-ID: <20201216175828.GQ3040@hirez.programming.kicks-ass.net> (raw) In-Reply-To: <20201216165605.4h5q7os5dutjgdqi@treble> On Wed, Dec 16, 2020 at 10:56:05AM -0600, Josh Poimboeuf wrote: > On Wed, Dec 16, 2020 at 09:40:59AM +0100, Peter Zijlstra wrote: > > > Could we make it easier by caching the shared > > > per-alt-group CFI state somewhere along the way? > > > > Yes, but when I tried it grew the code required. Runtime costs would be > > less, but I figured that since alternatives are typically few and small, > > that wasn't a real consideration. > > Aren't alternatives going to be everywhere now with paravirt using them? What I meant was, they're either 2-3 wide and only a few instructions long. Which greatly bounds the actual complexity of the algorithm, however daft. > > No real objection, I just didn't do it because 1) it works, and 2) even > > moar lines. > > I'm kind of surprised it would need moar lines. Let me play around with > it and maybe I'll come around ;-) Please do, it could be getting all the niggly bits right exhausted my brain enough to miss the obvious ;-)
WARNING: multiple messages have this Message-ID (diff)
From: Peter Zijlstra <peterz@infradead.org> To: Josh Poimboeuf <jpoimboe@redhat.com> Cc: "Juri Lelli" <juri.lelli@redhat.com>, linux-hyperv@vger.kernel.org, "Daniel Lezcano" <daniel.lezcano@linaro.org>, "Wanpeng Li" <wanpengli@tencent.com>, kvm@vger.kernel.org, "VMware, Inc." <pv-drivers@vmware.com>, virtualization@lists.linux-foundation.org, "Ben Segall" <bsegall@google.com>, "H. Peter Anvin" <hpa@zytor.com>, "Boris Ostrovsky" <boris.ostrovsky@oracle.com>, "Wei Liu" <wei.liu@kernel.org>, "Stefano Stabellini" <sstabellini@kernel.org>, "Stephen Hemminger" <sthemmin@microsoft.com>, "Joerg Roedel" <joro@8bytes.org>, x86@kernel.org, "Ingo Molnar" <mingo@redhat.com>, "Mel Gorman" <mgorman@suse.de>, xen-devel@lists.xenproject.org, "Haiyang Zhang" <haiyangz@microsoft.com>, "Steven Rostedt" <rostedt@goodmis.org>, "Borislav Petkov" <bp@alien8.de>, luto@kernel.org, "Vincent Guittot" <vincent.guittot@linaro.org>, "Thomas Gleixner" <tglx@linutronix.de>, "Dietmar Eggemann" <dietmar.eggemann@arm.com>, "Jim Mattson" <jmattson@google.com>, "Jürgen Groß" <jgross@suse.com>, linux-kernel@vger.kernel.org, "Sean Christopherson" <sean.j.christopherson@intel.com>, "Paolo Bonzini" <pbonzini@redhat.com>, "Daniel Bristot de Oliveira" <bristot@redhat.com> Subject: Re: [PATCH v2 00/12] x86: major paravirt cleanup Date: Wed, 16 Dec 2020 18:58:28 +0100 [thread overview] Message-ID: <20201216175828.GQ3040@hirez.programming.kicks-ass.net> (raw) In-Reply-To: <20201216165605.4h5q7os5dutjgdqi@treble> On Wed, Dec 16, 2020 at 10:56:05AM -0600, Josh Poimboeuf wrote: > On Wed, Dec 16, 2020 at 09:40:59AM +0100, Peter Zijlstra wrote: > > > Could we make it easier by caching the shared > > > per-alt-group CFI state somewhere along the way? > > > > Yes, but when I tried it grew the code required. Runtime costs would be > > less, but I figured that since alternatives are typically few and small, > > that wasn't a real consideration. > > Aren't alternatives going to be everywhere now with paravirt using them? What I meant was, they're either 2-3 wide and only a few instructions long. Which greatly bounds the actual complexity of the algorithm, however daft. > > No real objection, I just didn't do it because 1) it works, and 2) even > > moar lines. > > I'm kind of surprised it would need moar lines. Let me play around with > it and maybe I'll come around ;-) Please do, it could be getting all the niggly bits right exhausted my brain enough to miss the obvious ;-) _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
next prev parent reply other threads:[~2020-12-16 18:00 UTC|newest] Thread overview: 107+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-11-20 11:46 [PATCH v2 00/12] x86: major paravirt cleanup Juergen Gross 2020-11-20 11:46 ` Juergen Gross via Virtualization 2020-11-20 11:46 ` [PATCH v2 01/12] x86/xen: use specific Xen pv interrupt entry for MCE Juergen Gross 2020-12-09 21:03 ` Thomas Gleixner 2020-11-20 11:46 ` [PATCH v2 02/12] x86/xen: use specific Xen pv interrupt entry for DF Juergen Gross 2020-12-09 21:03 ` Thomas Gleixner 2020-11-20 11:46 ` [PATCH v2 03/12] x86/pv: switch SWAPGS to ALTERNATIVE Juergen Gross 2020-11-20 11:46 ` Juergen Gross via Virtualization 2020-11-27 11:31 ` Borislav Petkov 2020-11-27 11:31 ` Borislav Petkov 2020-12-09 21:07 ` Thomas Gleixner 2020-12-09 21:07 ` Thomas Gleixner 2020-11-20 11:46 ` [PATCH v2 04/12] x86/xen: drop USERGS_SYSRET64 paravirt call Juergen Gross 2020-11-20 11:46 ` Juergen Gross via Virtualization 2020-12-02 12:32 ` Borislav Petkov 2020-12-02 12:32 ` Borislav Petkov 2020-12-02 14:48 ` Jürgen Groß 2020-12-02 14:48 ` Jürgen Groß via Virtualization 2020-12-02 17:08 ` Borislav Petkov 2020-12-02 17:08 ` Borislav Petkov 2020-11-20 11:46 ` [PATCH v2 05/12] x86: rework arch_local_irq_restore() to not use popf Juergen Gross 2020-11-20 11:46 ` Juergen Gross via Virtualization 2020-11-20 11:59 ` Peter Zijlstra 2020-11-20 11:59 ` Peter Zijlstra 2020-11-20 12:05 ` Jürgen Groß 2020-11-20 12:05 ` Jürgen Groß via Virtualization 2020-11-22 6:55 ` Jürgen Groß 2020-11-22 6:55 ` Jürgen Groß via Virtualization 2020-11-22 21:44 ` Andy Lutomirski 2020-11-22 21:44 ` Andy Lutomirski 2020-11-22 21:44 ` Andy Lutomirski 2020-11-23 5:21 ` Jürgen Groß 2020-11-23 5:21 ` Jürgen Groß via Virtualization 2020-11-23 15:15 ` Andy Lutomirski 2020-11-23 15:15 ` Andy Lutomirski 2020-12-09 13:27 ` Mark Rutland 2020-12-09 13:27 ` Mark Rutland 2020-12-09 14:02 ` Mark Rutland 2020-12-09 14:02 ` Mark Rutland 2020-12-09 14:05 ` Jürgen Groß 2020-12-09 14:05 ` Jürgen Groß via Virtualization 2020-12-09 18:15 ` Mark Rutland 2020-12-09 18:15 ` Mark Rutland 2020-12-09 18:54 ` Thomas Gleixner 2020-12-09 18:54 ` Thomas Gleixner 2020-12-10 11:10 ` Mark Rutland 2020-12-10 11:10 ` Mark Rutland 2020-12-10 20:15 ` x86/ioapic: Cleanup the timer_works() irqflags mess Thomas Gleixner 2020-12-10 20:15 ` Thomas Gleixner 2020-12-10 22:04 ` [tip: x86/apic] " tip-bot2 for Thomas Gleixner 2020-12-11 5:10 ` Jürgen Groß 2020-12-11 5:10 ` Jürgen Groß via Virtualization 2020-11-27 2:20 ` [x86] 97e8f0134a: fio.write_iops 8.6% improvement kernel test robot 2020-11-20 11:46 ` [PATCH v2 06/12] x86/paravirt: switch time pvops functions to use static_call() Juergen Gross 2020-11-20 11:46 ` Juergen Gross via Virtualization 2020-11-20 12:01 ` Peter Zijlstra 2020-11-20 12:01 ` Peter Zijlstra 2020-11-20 12:07 ` Jürgen Groß 2020-11-20 12:07 ` Jürgen Groß via Virtualization 2020-11-20 11:46 ` [PATCH v2 07/12] x86: add new features for paravirt patching Juergen Gross 2020-12-08 18:43 ` Borislav Petkov 2020-12-09 7:30 ` Jürgen Groß 2020-12-09 12:03 ` Borislav Petkov 2020-12-09 12:22 ` Jürgen Groß 2020-12-10 17:58 ` Borislav Petkov 2020-11-20 11:46 ` [PATCH v2 08/12] x86/paravirt: remove no longer needed 32-bit pvops cruft Juergen Gross 2020-11-20 11:46 ` Juergen Gross via Virtualization 2020-11-20 12:08 ` Peter Zijlstra 2020-11-20 12:08 ` Peter Zijlstra 2020-11-20 12:16 ` Jürgen Groß 2020-11-20 12:16 ` Jürgen Groß via Virtualization 2020-11-20 16:52 ` Arvind Sankar 2020-11-20 11:46 ` [PATCH v2 09/12] x86/paravirt: switch iret pvops to ALTERNATIVE Juergen Gross 2020-11-20 11:46 ` Juergen Gross via Virtualization 2020-11-20 11:46 ` [PATCH v2 10/12] x86/paravirt: add new macros PVOP_ALT* supporting pvops in ALTERNATIVEs Juergen Gross 2020-11-20 11:46 ` Juergen Gross via Virtualization 2020-11-20 11:46 ` [PATCH v2 11/12] x86/paravirt: switch functions with custom code to ALTERNATIVE Juergen Gross 2020-11-20 11:46 ` Juergen Gross via Virtualization 2020-11-20 15:46 ` kernel test robot 2020-11-20 15:46 ` kernel test robot 2020-11-20 15:46 ` kernel test robot 2020-11-25 15:46 ` [x86/paravirt] fd8d46a7a2: kernel-selftests.livepatch.test-callbacks.sh.fail kernel test robot 2020-11-20 11:46 ` [PATCH v2 12/12] x86/paravirt: have only one paravirt patch function Juergen Gross 2020-11-20 11:46 ` Juergen Gross via Virtualization 2020-11-20 14:18 ` kernel test robot 2020-11-20 14:18 ` kernel test robot 2020-11-20 14:18 ` kernel test robot 2020-11-20 12:53 ` [PATCH v2 00/12] x86: major paravirt cleanup Peter Zijlstra 2020-11-20 12:53 ` Peter Zijlstra 2020-11-23 13:43 ` Peter Zijlstra 2020-11-23 13:43 ` Peter Zijlstra 2020-12-15 11:42 ` Jürgen Groß 2020-12-15 11:42 ` Jürgen Groß via Virtualization 2020-12-15 14:18 ` Peter Zijlstra 2020-12-15 14:18 ` Peter Zijlstra 2020-12-15 14:54 ` Peter Zijlstra 2020-12-15 14:54 ` Peter Zijlstra 2020-12-15 15:07 ` Jürgen Groß 2020-12-15 15:07 ` Jürgen Groß via Virtualization 2020-12-16 0:38 ` Josh Poimboeuf 2020-12-16 0:38 ` Josh Poimboeuf 2020-12-16 8:40 ` Peter Zijlstra 2020-12-16 8:40 ` Peter Zijlstra 2020-12-16 16:56 ` Josh Poimboeuf 2020-12-16 16:56 ` Josh Poimboeuf 2020-12-16 17:58 ` Peter Zijlstra [this message] 2020-12-16 17:58 ` Peter Zijlstra
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