From: Quentin Perret <qperret@google.com>
To: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Marc Zyngier <maz@kernel.org>, James Morse <james.morse@arm.com>,
Julien Thierry <julien.thierry.kdev@gmail.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Rob Herring <robh+dt@kernel.org>,
Frank Rowand <frowand.list@gmail.com>,
devicetree@vger.kernel.org, android-kvm@google.com,
linux-kernel@vger.kernel.org, kernel-team@android.com,
kvmarm@lists.cs.columbia.edu,
linux-arm-kernel@lists.infradead.org,
Fuad Tabba <tabba@google.com>,
Mark Rutland <mark.rutland@arm.com>,
David Brazdil <dbrazdil@google.com>
Subject: Re: [RFC PATCH v2 21/26] KVM: arm64: Refactor kvm_arm_setup_stage2()
Date: Thu, 4 Feb 2021 14:07:04 +0000 [thread overview]
Message-ID: <YBv/iEl/Bjlte+yq@google.com> (raw)
In-Reply-To: <20210203155354.GE18974@willie-the-truck>
On Wednesday 03 Feb 2021 at 15:53:54 (+0000), Will Deacon wrote:
> On Fri, Jan 08, 2021 at 12:15:19PM +0000, Quentin Perret wrote:
> > In order to re-use some of the stage 2 setup at EL2, factor parts of
> > kvm_arm_setup_stage2() out into static inline functions.
> >
> > No functional change intended.
> >
> > Signed-off-by: Quentin Perret <qperret@google.com>
> > ---
> > arch/arm64/include/asm/kvm_mmu.h | 48 ++++++++++++++++++++++++++++++++
> > arch/arm64/kvm/reset.c | 42 +++-------------------------
> > 2 files changed, 52 insertions(+), 38 deletions(-)
> >
> > diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
> > index 662f0415344e..83b4c5cf4768 100644
> > --- a/arch/arm64/include/asm/kvm_mmu.h
> > +++ b/arch/arm64/include/asm/kvm_mmu.h
> > @@ -280,6 +280,54 @@ static inline int kvm_write_guest_lock(struct kvm *kvm, gpa_t gpa,
> > return ret;
> > }
> >
> > +static inline u64 kvm_get_parange(u64 mmfr0)
> > +{
> > + u64 parange = cpuid_feature_extract_unsigned_field(mmfr0,
> > + ID_AA64MMFR0_PARANGE_SHIFT);
> > + if (parange > ID_AA64MMFR0_PARANGE_MAX)
> > + parange = ID_AA64MMFR0_PARANGE_MAX;
> > +
> > + return parange;
> > +}
> > +
> > +/*
> > + * The VTCR value is common across all the physical CPUs on the system.
> > + * We use system wide sanitised values to fill in different fields,
> > + * except for Hardware Management of Access Flags. HA Flag is set
> > + * unconditionally on all CPUs, as it is safe to run with or without
> > + * the feature and the bit is RES0 on CPUs that don't support it.
> > + */
> > +static inline u64 kvm_get_vtcr(u64 mmfr0, u64 mmfr1, u32 phys_shift)
> > +{
> > + u64 vtcr = VTCR_EL2_FLAGS;
> > + u8 lvls;
> > +
> > + vtcr |= kvm_get_parange(mmfr0) << VTCR_EL2_PS_SHIFT;
> > + vtcr |= VTCR_EL2_T0SZ(phys_shift);
> > + /*
> > + * Use a minimum 2 level page table to prevent splitting
> > + * host PMD huge pages at stage2.
> > + */
> > + lvls = stage2_pgtable_levels(phys_shift);
> > + if (lvls < 2)
> > + lvls = 2;
> > + vtcr |= VTCR_EL2_LVLS_TO_SL0(lvls);
> > +
> > + /*
> > + * Enable the Hardware Access Flag management, unconditionally
> > + * on all CPUs. The features is RES0 on CPUs without the support
> > + * and must be ignored by the CPUs.
> > + */
> > + vtcr |= VTCR_EL2_HA;
> > +
> > + /* Set the vmid bits */
> > + vtcr |= (get_vmid_bits(mmfr1) == 16) ?
> > + VTCR_EL2_VS_16BIT :
> > + VTCR_EL2_VS_8BIT;
> > +
> > + return vtcr;
> > +}
>
> Although I think this is functionally fine, I think it's unusual to see
> large "static inline" functions like this in shared header files. One
> alternative approach would be to follow the example of
> kernel/locking/qspinlock_paravirt.h, where the header is guarded in such a
> way that is only ever included by kernel/locking/qspinlock.c and therefore
> doesn't need the "inline" at all. That separation really helps, I think.
Alternatively, I might be able to have an mmu.c file in the hyp/ folder,
and to compile it for both the host kernel and the EL2 obj as we do for
a few things already. Or maybe I'll just stick it in pgtable.c. Either
way, it'll add a function call, but I can't really see that having any
measurable impact, so we should be fine.
Cheers,
Quentin
next prev parent reply other threads:[~2021-02-04 14:11 UTC|newest]
Thread overview: 97+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-08 12:14 [RFC PATCH v2 00/26] KVM/arm64: A stage 2 for the host Quentin Perret
2021-01-08 12:14 ` [RFC PATCH v2 01/26] arm64: lib: Annotate {clear,copy}_page() as position-independent Quentin Perret
2021-01-08 12:15 ` [RFC PATCH v2 02/26] KVM: arm64: Link position-independent string routines into .hyp.text Quentin Perret
2021-01-08 12:15 ` [RFC PATCH v2 03/26] arm64: kvm: Add standalone ticket spinlock implementation for use at hyp Quentin Perret
2021-02-01 17:28 ` Will Deacon
2021-02-01 17:40 ` Quentin Perret
2021-01-08 12:15 ` [RFC PATCH v2 04/26] KVM: arm64: Initialize kvm_nvhe_init_params early Quentin Perret
2021-02-01 17:41 ` Will Deacon
2021-01-08 12:15 ` [RFC PATCH v2 05/26] KVM: arm64: Avoid free_page() in page-table allocator Quentin Perret
2021-02-01 17:46 ` Will Deacon
2021-01-08 12:15 ` [RFC PATCH v2 06/26] KVM: arm64: Factor memory allocation out of pgtable.c Quentin Perret
2021-02-01 18:16 ` Will Deacon
2021-02-01 18:32 ` Quentin Perret
2021-02-01 18:39 ` Will Deacon
2021-01-08 12:15 ` [RFC PATCH v2 07/26] KVM: arm64: Introduce a BSS section for use at Hyp Quentin Perret
2021-02-01 18:32 ` Will Deacon
2021-01-08 12:15 ` [RFC PATCH v2 08/26] KVM: arm64: Make kvm_call_hyp() a function call " Quentin Perret
2021-02-01 18:41 ` Will Deacon
2021-01-08 12:15 ` [RFC PATCH v2 09/26] KVM: arm64: Allow using kvm_nvhe_sym() in hyp code Quentin Perret
2021-02-01 18:43 ` Will Deacon
2021-01-08 12:15 ` [RFC PATCH v2 10/26] KVM: arm64: Introduce an early Hyp page allocator Quentin Perret
2021-02-01 19:00 ` Will Deacon
2021-02-02 9:44 ` Quentin Perret
2021-01-08 12:15 ` [RFC PATCH v2 11/26] KVM: arm64: Stub CONFIG_DEBUG_LIST at Hyp Quentin Perret
2021-02-01 19:06 ` Will Deacon
2021-02-02 9:57 ` Quentin Perret
2021-02-02 10:00 ` Will Deacon
2021-02-02 10:14 ` Quentin Perret
2021-01-08 12:15 ` [RFC PATCH v2 12/26] KVM: arm64: Introduce a Hyp buddy page allocator Quentin Perret
2021-02-02 18:13 ` Will Deacon
2021-02-03 18:33 ` Quentin Perret
2021-02-04 14:31 ` Will Deacon
2021-02-04 14:52 ` Quentin Perret
2021-02-04 17:48 ` Will Deacon
2021-02-04 18:01 ` Quentin Perret
2021-02-04 18:13 ` Will Deacon
2021-02-04 18:24 ` Quentin Perret
2021-02-04 18:19 ` Quentin Perret
2021-02-04 18:24 ` Will Deacon
2021-02-04 18:32 ` Quentin Perret
2021-01-08 12:15 ` [RFC PATCH v2 13/26] KVM: arm64: Enable access to sanitized CPU features at EL2 Quentin Perret
2021-01-13 11:33 ` Marc Zyngier
2021-01-13 14:23 ` Quentin Perret
2021-01-13 14:35 ` Quentin Perret
2021-01-13 17:27 ` Marc Zyngier
2021-01-13 18:28 ` Quentin Perret
2021-01-08 12:15 ` [RFC PATCH v2 14/26] KVM: arm64: Factor out vector address calculation Quentin Perret
2021-02-02 18:24 ` Will Deacon
2021-01-08 12:15 ` [RFC PATCH v2 15/26] of/fdt: Introduce early_init_dt_add_memory_hyp() Quentin Perret
2021-01-11 14:45 ` Rob Herring
2021-01-12 9:51 ` Quentin Perret
2021-01-12 14:10 ` Rob Herring
2021-01-12 14:26 ` Quentin Perret
2021-01-12 15:53 ` Rob Herring
2021-01-12 16:15 ` Quentin Perret
2021-01-12 16:45 ` Rob Herring
2021-01-12 16:50 ` Quentin Perret
2021-01-15 11:49 ` Quentin Perret
2021-01-08 12:15 ` [RFC PATCH v2 16/26] KVM: arm64: Prepare Hyp memory protection Quentin Perret
2021-02-03 14:37 ` Will Deacon
2021-02-04 10:47 ` Quentin Perret
2021-02-05 17:56 ` Will Deacon
2021-02-09 10:00 ` Quentin Perret
2021-02-09 12:23 ` Will Deacon
2021-02-19 18:32 ` Sean Christopherson
2021-02-22 11:04 ` Quentin Perret
2021-01-08 12:15 ` [RFC PATCH v2 17/26] KVM: arm64: Elevate Hyp mappings creation at EL2 Quentin Perret
2021-02-03 15:31 ` Will Deacon
2021-02-04 11:08 ` Quentin Perret
2021-02-05 18:01 ` Will Deacon
2021-01-08 12:15 ` [RFC PATCH v2 18/26] KVM: arm64: Use kvm_arch for stage 2 pgtable Quentin Perret
2021-02-03 15:34 ` Will Deacon
2021-01-08 12:15 ` [RFC PATCH v2 19/26] KVM: arm64: Use kvm_arch in kvm_s2_mmu Quentin Perret
2021-02-03 15:38 ` Will Deacon
2021-01-08 12:15 ` [RFC PATCH v2 20/26] KVM: arm64: Set host stage 2 using kvm_nvhe_init_params Quentin Perret
2021-02-03 16:05 ` Will Deacon
2021-01-08 12:15 ` [RFC PATCH v2 21/26] KVM: arm64: Refactor kvm_arm_setup_stage2() Quentin Perret
2021-02-03 15:53 ` Will Deacon
2021-02-04 14:07 ` Quentin Perret [this message]
2021-01-08 12:15 ` [RFC PATCH v2 22/26] KVM: arm64: Refactor __load_guest_stage2() Quentin Perret
2021-02-03 15:54 ` Will Deacon
2021-01-08 12:15 ` [RFC PATCH v2 23/26] KVM: arm64: Refactor __populate_fault_info() Quentin Perret
2021-02-03 15:58 ` Will Deacon
2021-02-04 14:18 ` Quentin Perret
2021-01-08 12:15 ` [RFC PATCH v2 24/26] KVM: arm64: Make memcache anonymous in pgtable allocator Quentin Perret
2021-02-03 15:59 ` Will Deacon
2021-02-04 14:24 ` Quentin Perret
2021-02-04 14:36 ` Will Deacon
2021-01-08 12:15 ` [RFC PATCH v2 25/26] KVM: arm64: Reserve memory for host stage 2 Quentin Perret
2021-01-08 12:15 ` [RFC PATCH v2 26/26] KVM: arm64: Wrap the host with a " Quentin Perret
2021-02-03 16:11 ` Will Deacon
2021-02-04 14:26 ` Quentin Perret
2021-02-04 14:37 ` Will Deacon
2021-02-17 16:27 ` [RFC PATCH v2 00/26] KVM/arm64: A stage 2 for the host Mate Toth-Pal
2021-02-17 17:24 ` Quentin Perret
2021-02-19 17:54 ` Sean Christopherson
2021-02-19 17:57 ` Quentin Perret
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