From: christoffer.dall@linaro.org (Christoffer Dall)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 1/3] arm64: KVM: Implement 48 VA support for KVM EL2 and Stage-2
Date: Wed, 8 Oct 2014 11:48:10 +0200 [thread overview]
Message-ID: <20141008094810.GM3717@cbox> (raw)
In-Reply-To: <5433ED4B.10000@arm.com>
On Tue, Oct 07, 2014 at 02:40:27PM +0100, Marc Zyngier wrote:
> Hi Christoffer,
>
> On 06/10/14 21:30, Christoffer Dall wrote:
> > This patch adds the necessary support for all host kernel PGSIZE and
> > VA_SPACE configuration options for both EL2 and the Stage-2 page tables.
> >
> > However, for 40bit and 42bit PARange systems, the architecture mandates
> > that VTCR_EL2.SL0 is maximum 1, resulting in fewer levels of stage-2
> > pagge tables than levels of host kernel page tables. At the same time,
> > systems with a PARange > 42bit, we limit the IPA range by always setting
> > VTCR_EL2.T0SZ to 24.
> >
> > To solve the situation with different levels of page tables for Stage-2
> > translation than the host kernel page tables, we allocate a dummy PGD
> > with pointers to our actual inital level Stage-2 page table, in order
> > for us to reuse the kernel pgtable manipulation primitives. Reproducing
> > all these in KVM does not look pretty and unnecessarily complicates the
> > 32-bit side.
> >
> > Systems with a PARange < 40bits are not yet supported.
> >
> > [ I have reworked this patch from its original form submitted by
> > Jungseok to take the architecture constraints into consideration.
> > There were too many changes from the original patch for me to
> > preserve the authorship. Thanks to Catalin Marinas for his help in
> > figuring out a good solution to this challenge. I have also fixed
> > various bugs and missing error code handling from the original
> > patch. - Christoffer ]
> >
> > Cc: Marc Zyngier <marc.zyngier@arm.com>
> > Cc: Catalin Marinas <catalin.marinas@arm.com>
> > Signed-off-by: Jungseok Lee <jungseoklee85@gmail.com>
> > Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
>
> On top of Catalin's review, I have the following comments:
>
> [...]
>
> > diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
> > index bb06f76..3b3e18f 100644
> > --- a/arch/arm/kvm/mmu.c
> > +++ b/arch/arm/kvm/mmu.c
> > @@ -42,7 +42,7 @@ static unsigned long hyp_idmap_start;
> > static unsigned long hyp_idmap_end;
> > static phys_addr_t hyp_idmap_vector;
> >
> > -#define pgd_order get_order(PTRS_PER_PGD * sizeof(pgd_t))
> > +#define hyp_pgd_order get_order(PTRS_PER_PGD * sizeof(pgd_t))
> >
> > #define kvm_pmd_huge(_x) (pmd_huge(_x) || pmd_trans_huge(_x))
> >
> > @@ -158,7 +158,7 @@ static void unmap_pmds(struct kvm *kvm, pud_t *pud,
> > }
> > } while (pmd++, addr = next, addr != end);
> >
> > - if (kvm_pmd_table_empty(start_pmd))
> > + if (kvm_pmd_table_empty(start_pmd) && (!kvm || KVM_PREALLOC_LEVEL < 2))
>
> This really feels clunky. Can we fold the additional tests inside
> kvm_pmd_table_empty(), taking kvm as an additional parameter?
>
> > clear_pud_entry(kvm, pud, start_addr);
> > }
> >
> > @@ -182,7 +182,7 @@ static void unmap_puds(struct kvm *kvm, pgd_t *pgd,
> > }
> > } while (pud++, addr = next, addr != end);
> >
> > - if (kvm_pud_table_empty(start_pud))
> > + if (kvm_pud_table_empty(start_pud) && (!kvm || KVM_PREALLOC_LEVEL < 1))
>
> Same here.
>
Sounds reasonable, I'll try to work it into the next version of the
patches.
-Christoffer
next prev parent reply other threads:[~2014-10-08 9:48 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-06 20:30 [PATCH v2 0/3] arm/arm64: KVM: Host 48-bit VA support and IPA limits Christoffer Dall
2014-10-06 20:30 ` [PATCH v2 1/3] arm64: KVM: Implement 48 VA support for KVM EL2 and Stage-2 Christoffer Dall
2014-10-07 10:48 ` Catalin Marinas
2014-10-07 13:28 ` Marc Zyngier
2014-10-07 19:39 ` Christoffer Dall
2014-10-08 9:34 ` Marc Zyngier
2014-10-08 9:47 ` Christoffer Dall
2014-10-08 10:27 ` Marc Zyngier
2014-10-08 9:47 ` Catalin Marinas
2014-10-09 11:01 ` Christoffer Dall
2014-10-09 13:36 ` Catalin Marinas
2014-10-10 8:16 ` Christoffer Dall
2014-10-07 13:40 ` Marc Zyngier
2014-10-08 9:48 ` Christoffer Dall [this message]
2014-10-06 20:30 ` [PATCH v2 2/3] arm/arm64: KVM: Ensure memslots are within KVM_PHYS_SIZE Christoffer Dall
2014-10-06 20:30 ` [PATCH v2 3/3] arm64: Allow 48-bits VA space without ARM_SMMU Christoffer Dall
2014-10-07 9:24 ` [PATCH v2 0/3] arm/arm64: KVM: Host 48-bit VA support and IPA limits Catalin Marinas
2014-10-07 9:36 ` Christoffer Dall
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