From: Andrew Murray <andrew.murray@arm.com>
To: Marc Zyngier <maz@kernel.org>
Cc: kvm@vger.kernel.org, Catalin Marinas <catalin.marinas@arm.com>,
linux-kernel@vger.kernel.org, Sudeep Holla <sudeep.holla@arm.com>,
will@kernel.org, kvmarm@lists.cs.columbia.edu,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 02/18] arm64: KVM: reset E2PB correctly in MDCR_EL2 when exiting the guest(VHE)
Date: Tue, 24 Dec 2019 10:29:50 +0000 [thread overview]
Message-ID: <20191224102949.GD42593@e119886-lin.cambridge.arm.com> (raw)
In-Reply-To: <20191221131214.769a140e@why>
On Sat, Dec 21, 2019 at 01:12:14PM +0000, Marc Zyngier wrote:
> On Fri, 20 Dec 2019 14:30:09 +0000
> Andrew Murray <andrew.murray@arm.com> wrote:
>
> > From: Sudeep Holla <sudeep.holla@arm.com>
> >
> > On VHE systems, the reset value for MDCR_EL2.E2PB=b00 which defaults
> > to profiling buffer using the EL2 stage 1 translations.
>
> Does the reset value actually matter here? I don't see it being
> specific to VHE systems, and all we're trying to achieve is to restore
> the SPE configuration to a state where it can be used by the host.
>
> > However if the
> > guest are allowed to use profiling buffers changing E2PB settings, we
>
> How can the guest be allowed to change E2PB settings? Or do you mean
> here that allowing the guest to use SPE will mandate changes of the
> E2PB settings, and that we'd better restore the hypervisor state once
> we exit?
>
> > need to ensure we resume back MDCR_EL2.E2PB=b00. Currently we just
> > do bitwise '&' with MDCR_EL2_E2PB_MASK which will retain the value.
> >
> > So fix it by clearing all the bits in E2PB.
> >
> > Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
> > Signed-off-by: Andrew Murray <andrew.murray@arm.com>
> > ---
> > arch/arm64/kvm/hyp/switch.c | 4 +---
> > 1 file changed, 1 insertion(+), 3 deletions(-)
> >
> > diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
> > index 72fbbd86eb5e..250f13910882 100644
> > --- a/arch/arm64/kvm/hyp/switch.c
> > +++ b/arch/arm64/kvm/hyp/switch.c
> > @@ -228,9 +228,7 @@ void deactivate_traps_vhe_put(void)
> > {
> > u64 mdcr_el2 = read_sysreg(mdcr_el2);
> >
> > - mdcr_el2 &= MDCR_EL2_HPMN_MASK |
> > - MDCR_EL2_E2PB_MASK << MDCR_EL2_E2PB_SHIFT |
> > - MDCR_EL2_TPMS;
> > + mdcr_el2 &= MDCR_EL2_HPMN_MASK | MDCR_EL2_TPMS;
> >
> > write_sysreg(mdcr_el2, mdcr_el2);
> >
>
> I'm OK with this change, but I believe the commit message could use
> some tidying up.
No problem, I'll update the commit message.
Thanks,
Andrew Murray
>
> Thanks,
>
> M.
> --
> Jazz is not dead. It just smells funny...
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next prev parent reply other threads:[~2019-12-24 10:29 UTC|newest]
Thread overview: 78+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-20 14:30 [PATCH v2 00/18] arm64: KVM: add SPE profiling support Andrew Murray
2019-12-20 14:30 ` [PATCH v2 01/18] dt-bindings: ARM SPE: highlight the need for PPI partitions on heterogeneous systems Andrew Murray
2019-12-20 14:30 ` [PATCH v2 02/18] arm64: KVM: reset E2PB correctly in MDCR_EL2 when exiting the guest(VHE) Andrew Murray
2019-12-21 13:12 ` Marc Zyngier
2019-12-24 10:29 ` Andrew Murray [this message]
2020-01-02 16:21 ` Andrew Murray
2019-12-20 14:30 ` [PATCH v2 03/18] arm64: KVM: define SPE data structure for each vcpu Andrew Murray
2019-12-21 13:19 ` Marc Zyngier
2019-12-24 12:01 ` Andrew Murray
2019-12-20 14:30 ` [PATCH v2 04/18] arm64: KVM: add SPE system registers to sys_reg_descs Andrew Murray
2019-12-20 14:30 ` [PATCH v2 05/18] arm64: KVM/VHE: enable the use PMSCR_EL12 on VHE systems Andrew Murray
2019-12-20 14:30 ` [PATCH v2 06/18] arm64: KVM: split debug save restore across vm/traps activation Andrew Murray
2019-12-20 14:30 ` [PATCH v2 07/18] arm64: KVM/debug: drop pmscr_el1 and use sys_regs[PMSCR_EL1] in kvm_cpu_context Andrew Murray
2019-12-20 14:30 ` [PATCH v2 08/18] arm64: KVM: add support to save/restore SPE profiling buffer controls Andrew Murray
2019-12-21 13:57 ` Marc Zyngier
2019-12-24 10:49 ` Andrew Murray
2019-12-24 15:17 ` Andrew Murray
2019-12-24 15:48 ` Marc Zyngier
2019-12-20 14:30 ` [PATCH v2 09/18] arm64: KVM: enable conditional save/restore full " Andrew Murray
2019-12-20 18:06 ` Mark Rutland
2019-12-24 12:15 ` Andrew Murray
2019-12-21 14:13 ` Marc Zyngier
2020-01-07 15:13 ` Andrew Murray
2020-01-08 11:17 ` Marc Zyngier
2020-01-08 11:58 ` Will Deacon
2020-01-08 12:36 ` Marc Zyngier
2020-01-08 13:10 ` Will Deacon
2020-01-09 11:23 ` Andrew Murray
2020-01-09 11:25 ` Andrew Murray
2020-01-09 12:01 ` Will Deacon
2020-01-10 10:54 ` Andrew Murray
2020-01-10 11:04 ` Andrew Murray
2020-01-10 11:51 ` Marc Zyngier
2020-01-10 12:12 ` Andrew Murray
2020-01-10 11:18 ` Marc Zyngier
2020-01-10 12:12 ` Andrew Murray
2020-01-10 13:34 ` Marc Zyngier
2019-12-20 14:30 ` [PATCH v2 10/18] arm64: KVM/debug: use EL1&0 stage 1 translation regime Andrew Murray
2019-12-22 10:34 ` Marc Zyngier
2019-12-24 11:11 ` Andrew Murray
2020-01-13 16:31 ` Andrew Murray
2020-01-15 14:03 ` Marc Zyngier
2019-12-20 14:30 ` [PATCH v2 11/18] KVM: arm64: don't trap Statistical Profiling controls to EL2 Andrew Murray
2019-12-20 18:08 ` Mark Rutland
2019-12-22 10:42 ` Marc Zyngier
2019-12-23 11:56 ` Andrew Murray
2019-12-23 12:05 ` Marc Zyngier
2019-12-23 12:10 ` Andrew Murray
2020-01-09 17:25 ` Andrew Murray
2020-01-09 17:42 ` Mark Rutland
2020-01-09 17:46 ` Andrew Murray
2019-12-20 14:30 ` [PATCH v2 12/18] KVM: arm64: add a new vcpu device control group for SPEv1 Andrew Murray
2019-12-22 11:03 ` Marc Zyngier
2019-12-24 12:30 ` Andrew Murray
2019-12-20 14:30 ` [PATCH v2 13/18] perf: arm_spe: Add KVM structure for obtaining IRQ info Andrew Murray
2019-12-22 11:24 ` Marc Zyngier
2019-12-24 12:35 ` Andrew Murray
2019-12-20 14:30 ` [PATCH v2 14/18] KVM: arm64: spe: Provide guest virtual interrupts for SPE Andrew Murray
2019-12-22 12:07 ` Marc Zyngier
2019-12-24 11:50 ` Andrew Murray
2019-12-24 12:42 ` Marc Zyngier
2019-12-24 13:08 ` Andrew Murray
2019-12-24 13:22 ` Marc Zyngier
2019-12-24 13:36 ` Andrew Murray
2019-12-24 13:46 ` Marc Zyngier
2019-12-20 14:30 ` [PATCH v2 15/18] perf: arm_spe: Handle guest/host exclusion flags Andrew Murray
2019-12-20 18:10 ` Mark Rutland
2019-12-22 12:10 ` Marc Zyngier
2019-12-23 12:10 ` Andrew Murray
2019-12-23 12:18 ` Marc Zyngier
2019-12-20 14:30 ` [PATCH v2 16/18] KVM: arm64: enable SPE support Andrew Murray
2019-12-20 14:30 ` [PATCH v2 17/18, KVMTOOL] update_headers: Sync kvm UAPI headers with linux v5.5-rc2 Andrew Murray
2019-12-20 14:30 ` [PATCH v2 18/18, KVMTOOL] kvm: add a vcpu feature for SPEv1 support Andrew Murray
2019-12-20 17:55 ` [PATCH v2 00/18] arm64: KVM: add SPE profiling support Mark Rutland
2019-12-24 12:54 ` Andrew Murray
2019-12-21 10:48 ` Marc Zyngier
2019-12-22 12:22 ` Marc Zyngier
2019-12-24 12:56 ` Andrew Murray
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