linux-kernel - Re: [PATCH v2 03/16] KVM: arm64: Turn kvm_pgtable_stage2_set_owner into kvm_pgtable_stage2

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Message-ID: <20211006112222.ahfhtkhamdi3svm5@gator.home>
Date:   Wed, 6 Oct 2021 13:22:22 +0200
From:   Andrew Jones <drjones@...hat.com>
To:     Marc Zyngier <maz@...nel.org>
Cc:     linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.cs.columbia.edu,
        kvm@...r.kernel.org, linux-kernel@...r.kernel.org, will@...nel.org,
        qperret@...gle.com, dbrazdil@...gle.com,
        Steven Price <steven.price@....com>,
        Fuad Tabba <tabba@...gle.com>,
        Srivatsa Vaddagiri <vatsa@...eaurora.org>,
        Shanker R Donthineni <sdonthineni@...dia.com>,
        James Morse <james.morse@....com>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Alexandru Elisei <alexandru.elisei@....com>,
        kernel-team@...roid.com
Subject: Re: [PATCH v2 03/16] KVM: arm64: Turn kvm_pgtable_stage2_set_owner
 into kvm_pgtable_stage2_annotate

On Wed, Oct 06, 2021 at 01:02:11PM +0200, Andrew Jones wrote:
> On Mon, Oct 04, 2021 at 06:48:36PM +0100, Marc Zyngier wrote:
> > kvm_pgtable_stage2_set_owner() could be generalised into a way
> > to store up to 63 bits in the page tables, as long as we don't
> > set bit 0.
> > 
> > Let's just do that.
> > 
> > Signed-off-by: Marc Zyngier <maz@...nel.org>
> > ---
> >  arch/arm64/include/asm/kvm_pgtable.h          | 12 ++++++-----
> >  arch/arm64/kvm/hyp/include/nvhe/mem_protect.h |  2 +-
> >  arch/arm64/kvm/hyp/nvhe/mem_protect.c         | 11 ++++------
> >  arch/arm64/kvm/hyp/nvhe/setup.c               | 10 +++++++++-
> >  arch/arm64/kvm/hyp/pgtable.c                  | 20 ++++++-------------
> >  5 files changed, 27 insertions(+), 28 deletions(-)
> > 
> > diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h
> > index 027783829584..d4d3ae0b5edb 100644
> > --- a/arch/arm64/include/asm/kvm_pgtable.h
> > +++ b/arch/arm64/include/asm/kvm_pgtable.h
> > @@ -329,14 +329,16 @@ int kvm_pgtable_stage2_map(struct kvm_pgtable *pgt, u64 addr, u64 size,
> >  			   void *mc);
> >  
> >  /**
> > - * kvm_pgtable_stage2_set_owner() - Unmap and annotate pages in the IPA space to
> > - *				    track ownership.
> > + * kvm_pgtable_stage2_annotate() - Unmap and annotate pages in the IPA space
> > + *				   to track ownership (and more).
> >   * @pgt:	Page-table structure initialised by kvm_pgtable_stage2_init*().
> >   * @addr:	Base intermediate physical address to annotate.
> >   * @size:	Size of the annotated range.
> >   * @mc:		Cache of pre-allocated and zeroed memory from which to allocate
> >   *		page-table pages.
> > - * @owner_id:	Unique identifier for the owner of the page.
> > + * @annotation:	A 63 bit value that will be stored in the page tables.
> > + *		@annotation[0] must be 0, and @annotation[63:1] is stored
> > + *		in the page tables.
> >   *
> >   * By default, all page-tables are owned by identifier 0. This function can be
> >   * used to mark portions of the IPA space as owned by other entities. When a
> > @@ -345,8 +347,8 @@ int kvm_pgtable_stage2_map(struct kvm_pgtable *pgt, u64 addr, u64 size,
> >   *
> >   * Return: 0 on success, negative error code on failure.
> >   */
> > -int kvm_pgtable_stage2_set_owner(struct kvm_pgtable *pgt, u64 addr, u64 size,
> > -				 void *mc, u8 owner_id);
> > +int kvm_pgtable_stage2_annotate(struct kvm_pgtable *pgt, u64 addr, u64 size,
> > +				void *mc, kvm_pte_t annotation);
> >  
> >  /**
> >   * kvm_pgtable_stage2_unmap() - Remove a mapping from a guest stage-2 page-table.
> > diff --git a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
> > index b58c910babaf..9d2ca173ea9a 100644
> > --- a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
> > +++ b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
> > @@ -53,7 +53,7 @@ int __pkvm_host_share_hyp(u64 pfn);
> >  
> >  bool addr_is_memory(phys_addr_t phys);
> >  int host_stage2_idmap_locked(phys_addr_t addr, u64 size, enum kvm_pgtable_prot prot);
> > -int host_stage2_set_owner_locked(phys_addr_t addr, u64 size, u8 owner_id);
> > +int host_stage2_annotate_locked(phys_addr_t addr, u64 size, kvm_pte_t owner_id);
> >  int kvm_host_prepare_stage2(void *pgt_pool_base);
> >  void handle_host_mem_abort(struct kvm_cpu_context *host_ctxt);
> >  
> > diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
> > index bacd493a4eac..8cd0c3bdb911 100644
> > --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c
> > +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
> > @@ -286,17 +286,14 @@ static int host_stage2_adjust_range(u64 addr, struct kvm_mem_range *range)
> >  int host_stage2_idmap_locked(phys_addr_t addr, u64 size,
> >  			     enum kvm_pgtable_prot prot)
> >  {
> > -	hyp_assert_lock_held(&host_kvm.lock);
> > -
> >  	return host_stage2_try(__host_stage2_idmap, addr, addr + size, prot);
> >  }
> >  
> > -int host_stage2_set_owner_locked(phys_addr_t addr, u64 size, u8 owner_id)
> > +int host_stage2_annotate_locked(phys_addr_t addr, u64 size,
> > +				kvm_pte_t annotation)
> >  {
> > -	hyp_assert_lock_held(&host_kvm.lock);
> 
> Hi Marc,
> 
> Why are the lock asserts getting dropped?

Ah, I see. host_stage2_try already has the same assert.

Reviewed-by: Andrew Jones <drjones@...hat.com>

Thanks,
drew