From: Sean Christopherson <seanjc@google.com>
To: Zhu Lingshan <lingshan.zhu@intel.com>
Cc: peterz@infradead.org, pbonzini@redhat.com, bp@alien8.de,
vkuznets@redhat.com, wanpengli@tencent.com, jmattson@google.com,
joro@8bytes.org, kan.liang@linux.intel.com, ak@linux.intel.com,
wei.w.wang@intel.com, eranian@google.com,
liuxiangdong5@huawei.com, linux-kernel@vger.kernel.org,
x86@kernel.org, kvm@vger.kernel.org, like.xu.linux@gmail.com,
boris.ostrvsky@oracle.com, Like Xu <like.xu@linux.intel.com>,
Will Deacon <will@kernel.org>, Marc Zyngier <maz@kernel.org>,
Guo Ren <guoren@kernel.org>, Nick Hu <nickhu@andestech.com>,
Paul Walmsley <paul.walmsley@sifive.com>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
linux-arm-kernel@lists.infradead.org,
kvmarm@lists.cs.columbia.edu, linux-csky@vger.kernel.org,
linux-riscv@lists.infradead.org, xen-devel@lists.xenproject.org
Subject: Re: [PATCH V10 01/18] perf/core: Use static_call to optimize perf_guest_info_callbacks
Date: Fri, 27 Aug 2021 17:23:05 +0000 [thread overview]
Message-ID: <YSkfeXcd6nUT3AOJ@google.com> (raw)
In-Reply-To: <20210806133802.3528-2-lingshan.zhu@intel.com>
On Fri, Aug 06, 2021, Zhu Lingshan wrote:
> @@ -2944,18 +2966,21 @@ static unsigned long code_segment_base(struct pt_regs *regs)
>
> unsigned long perf_instruction_pointer(struct pt_regs *regs)
> {
> - if (perf_guest_cbs && perf_guest_cbs->is_in_guest())
> - return perf_guest_cbs->get_guest_ip();
> + unsigned long ip = static_call(x86_guest_get_ip)();
> +
> + if (likely(!ip))
Pivoting on ip==0 isn't correct, it's perfectly legal for a guest to execute
from %rip=0. Unless there's some static_call() magic that supports this with a
default function:
if (unlikely(!static_call(x86_guest_get_ip)(&ip)))
regs->ip + code_segment_base(regs)
return ip;
The easiest thing is keep the existing:
if (unlikely(static_call(x86_guest_state)()))
return static_call(x86_guest_get_ip)();
return regs->ip + code_segment_base(regs);
It's an extra call for PMIs in guest, but I don't think any of the KVM folks care
_that_ much about the performance in this case.
> + ip = regs->ip + code_segment_base(regs);
>
> - return regs->ip + code_segment_base(regs);
> + return ip;
> }
next prev parent reply other threads:[~2021-08-27 17:23 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-06 13:37 [PATCH V10 00/18] KVM: x86/pmu: Add *basic* support to enable guest PEBS via DS Zhu Lingshan
2021-08-06 13:37 ` [PATCH V10 01/18] perf/core: Use static_call to optimize perf_guest_info_callbacks Zhu Lingshan
2021-08-26 19:59 ` Sean Christopherson
2021-08-27 6:31 ` Like Xu
2021-09-15 1:19 ` Zhu, Lingshan
2021-09-21 23:22 ` Sean Christopherson
2021-08-27 17:23 ` Sean Christopherson [this message]
2021-08-06 13:37 ` [PATCH V10 02/18] perf/x86/intel: Add EPT-Friendly PEBS for Ice Lake Server Zhu Lingshan
2021-08-06 13:37 ` [PATCH V10 03/18] perf/x86/intel: Handle guest PEBS overflow PMI for KVM guest Zhu Lingshan
2021-08-06 13:37 ` [PATCH V10 04/18] perf/x86/core: Pass "struct kvm_pmu *" to determine the guest values Zhu Lingshan
2021-08-06 13:37 ` [PATCH V10 05/18] KVM: x86/pmu: Set MSR_IA32_MISC_ENABLE_EMON bit when vPMU is enabled Zhu Lingshan
2021-11-07 10:14 ` Liuxiangdong
2021-11-08 3:06 ` Like Xu
2021-11-08 4:07 ` Liuxiangdong
2021-11-08 4:11 ` Like Xu
2021-11-08 8:27 ` Liuxiangdong
2021-11-08 8:44 ` Like Xu
2021-11-08 10:06 ` Liuxiangdong
2021-08-06 13:37 ` [PATCH V10 06/18] KVM: x86/pmu: Introduce the ctrl_mask value for fixed counter Zhu Lingshan
2021-08-06 13:37 ` [PATCH V10 07/18] x86/perf/core: Add pebs_capable to store valid PEBS_COUNTER_MASK value Zhu Lingshan
2021-08-06 13:37 ` [PATCH V10 08/18] KVM: x86/pmu: Add IA32_PEBS_ENABLE MSR emulation for extended PEBS Zhu Lingshan
2021-08-06 13:37 ` [PATCH V10 09/18] KVM: x86/pmu: Reprogram PEBS event to emulate guest PEBS counter Zhu Lingshan
2021-08-06 13:37 ` [PATCH V10 10/18] KVM: x86/pmu: Adjust precise_ip to emulate Ice Lake guest PDIR counter Zhu Lingshan
2021-08-06 13:37 ` [PATCH V10 11/18] KVM: x86/pmu: Add IA32_DS_AREA MSR emulation to support guest DS Zhu Lingshan
2021-08-06 13:37 ` [PATCH V10 12/18] KVM: x86/pmu: Add PEBS_DATA_CFG MSR emulation to support adaptive PEBS Zhu Lingshan
2021-08-06 13:37 ` [PATCH V10 13/18] KVM: x86: Set PEBS_UNAVAIL in IA32_MISC_ENABLE when PEBS is enabled Zhu Lingshan
2021-08-06 13:37 ` [PATCH V10 14/18] KVM: x86/pmu: Move pmc_speculative_in_use() to arch/x86/kvm/pmu.h Zhu Lingshan
2021-08-06 13:37 ` [PATCH V10 15/18] KVM: x86/pmu: Disable guest PEBS temporarily in two rare situations Zhu Lingshan
2021-08-06 13:38 ` [PATCH V10 16/18] KVM: x86/pmu: Add kvm_pmu_cap to optimize perf_get_x86_pmu_capability Zhu Lingshan
2021-08-06 13:38 ` [PATCH V10 17/18] KVM: x86/cpuid: Refactor host/guest CPU model consistency check Zhu Lingshan
2021-08-06 13:38 ` [PATCH V10 18/18] KVM: x86/pmu: Expose CPUIDs feature bits PDCM, DS, DTES64 Zhu Lingshan
2021-08-18 5:27 ` [PATCH V10 00/18] KVM: x86/pmu: Add *basic* support to enable guest PEBS via DS Zhu, Lingshan
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