From: Fuad Tabba <tabba@google.com>
To: Quentin Perret <qperret@google.com>
Cc: kernel-team@android.com, qwandor@google.com, maz@kernel.org,
linux-kernel@vger.kernel.org, catalin.marinas@arm.com,
will@kernel.org, kvmarm@lists.cs.columbia.edu,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 01/14] KVM: arm64: Provide the host_stage2_try() helper macro
Date: Tue, 20 Jul 2021 14:57:19 +0100 [thread overview]
Message-ID: <CA+EHjTwL7M=Proo62mE5UFsGiYSGcNF2Pa7s9YOe5fiVVdRx-A@mail.gmail.com> (raw)
In-Reply-To: <20210719104735.3681732-2-qperret@google.com>
Hi Quentin,
On Mon, Jul 19, 2021 at 11:47 AM Quentin Perret <qperret@google.com> wrote:
>
> We currently unmap all MMIO mappings from the host stage-2 to recycle
> the pages whenever we run out. In order to make this pattern easy to
> re-use from other places, factor the logic out into a dedicated macro.
> While at it, apply the macro for the kvm_pgtable_stage2_set_owner()
> calls. They're currently only called early on and are guaranteed to
> succeed, but making them robust to the -ENOMEM case doesn't hurt and
> will avoid painful debugging sessions later on.
>
> Signed-off-by: Quentin Perret <qperret@google.com>
> ---
> arch/arm64/kvm/hyp/nvhe/mem_protect.c | 38 ++++++++++++++-------------
> 1 file changed, 20 insertions(+), 18 deletions(-)
>
> diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
> index d938ce95d3bd..56f2117c877b 100644
> --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c
> +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
> @@ -208,6 +208,23 @@ static inline int __host_stage2_idmap(u64 start, u64 end,
> prot, &host_s2_pool);
> }
>
> +/*
> + * The pool has been provided with enough pages to cover all of memory with
> + * page granularity, but it is difficult to know how much of the MMIO range
> + * we will need to cover upfront, so we may need to 'recycle' the pages if we
> + * run out.
> + */
> +#define host_stage2_try(fn, ...) \
> + ({ \
> + int __ret = fn(__VA_ARGS__); \
> + if (__ret == -ENOMEM) { \
> + __ret = host_stage2_unmap_dev_all(); \
> + if (!__ret) \
> + __ret = fn(__VA_ARGS__); \
> + } \
> + __ret; \
> + })
I think it might be good to document that this macro expects the
host_kvm.lock to be held.
Thanks,
/fuad
> static int host_stage2_idmap(u64 addr)
> {
> enum kvm_pgtable_prot prot = KVM_PGTABLE_PROT_R | KVM_PGTABLE_PROT_W;
> @@ -223,22 +240,7 @@ static int host_stage2_idmap(u64 addr)
> if (ret)
> goto unlock;
>
> - ret = __host_stage2_idmap(range.start, range.end, prot);
> - if (ret != -ENOMEM)
> - goto unlock;
> -
> - /*
> - * The pool has been provided with enough pages to cover all of memory
> - * with page granularity, but it is difficult to know how much of the
> - * MMIO range we will need to cover upfront, so we may need to 'recycle'
> - * the pages if we run out.
> - */
> - ret = host_stage2_unmap_dev_all();
> - if (ret)
> - goto unlock;
> -
> - ret = __host_stage2_idmap(range.start, range.end, prot);
> -
> + ret = host_stage2_try(__host_stage2_idmap, range.start, range.end, prot);
> unlock:
> hyp_spin_unlock(&host_kvm.lock);
>
> @@ -257,8 +259,8 @@ int __pkvm_mark_hyp(phys_addr_t start, phys_addr_t end)
> return -EINVAL;
>
> hyp_spin_lock(&host_kvm.lock);
> - ret = kvm_pgtable_stage2_set_owner(&host_kvm.pgt, start, end - start,
> - &host_s2_pool, pkvm_hyp_id);
> + ret = host_stage2_try(kvm_pgtable_stage2_set_owner, &host_kvm.pgt,
> + start, end - start, &host_s2_pool, pkvm_hyp_id);
> hyp_spin_unlock(&host_kvm.lock);
>
> return ret != -EAGAIN ? ret : 0;
> --
> 2.32.0.402.g57bb445576-goog
>
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next prev parent reply other threads:[~2021-07-20 13:58 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-19 10:47 [PATCH 00/14] Track shared pages at EL2 in protected mode Quentin Perret
2021-07-19 10:47 ` [PATCH 01/14] KVM: arm64: Provide the host_stage2_try() helper macro Quentin Perret
2021-07-20 13:57 ` Fuad Tabba [this message]
2021-07-19 10:47 ` [PATCH 02/14] KVM: arm64: Optimize kvm_pgtable_stage2_find_range() Quentin Perret
2021-07-19 10:47 ` [PATCH 03/14] KVM: arm64: Continue stage-2 map when re-creating mappings Quentin Perret
2021-07-19 12:14 ` Marc Zyngier
2021-07-19 13:32 ` Quentin Perret
2021-07-20 8:26 ` Marc Zyngier
2021-07-20 11:56 ` Quentin Perret
2021-07-19 10:47 ` [PATCH 04/14] KVM: arm64: Rename KVM_PTE_LEAF_ATTR_S2_IGNORED Quentin Perret
2021-07-19 10:47 ` [PATCH 05/14] KVM: arm64: Don't overwrite ignored bits with owner id Quentin Perret
2021-07-19 12:55 ` Marc Zyngier
2021-07-19 13:39 ` Quentin Perret
2021-07-20 8:46 ` Marc Zyngier
2021-07-19 10:47 ` [PATCH 06/14] KVM: arm64: Tolerate re-creating hyp mappings to set ignored bits Quentin Perret
2021-07-20 10:17 ` Fuad Tabba
2021-07-20 10:30 ` Quentin Perret
2021-07-20 10:59 ` Fuad Tabba
2021-07-20 11:14 ` Quentin Perret
2021-07-19 10:47 ` [PATCH 07/14] KVM: arm64: Enable forcing page-level stage-2 mappings Quentin Perret
2021-07-19 14:24 ` Marc Zyngier
2021-07-19 15:36 ` Quentin Perret
2021-07-19 10:47 ` [PATCH 08/14] KVM: arm64: Add support for tagging shared pages in page-table Quentin Perret
2021-07-19 14:43 ` Marc Zyngier
2021-07-19 15:49 ` Quentin Perret
2021-07-20 10:13 ` Marc Zyngier
2021-07-20 11:48 ` Quentin Perret
2021-07-20 13:48 ` Fuad Tabba
2021-07-20 14:06 ` Quentin Perret
2021-07-21 7:34 ` Fuad Tabba
2021-07-19 10:47 ` [PATCH 09/14] KVM: arm64: Mark host bss and rodata section as shared Quentin Perret
2021-07-19 15:01 ` Marc Zyngier
2021-07-19 15:56 ` Quentin Perret
2021-07-19 10:47 ` [PATCH 10/14] KVM: arm64: Enable retrieving protections attributes of PTEs Quentin Perret
2021-07-19 10:47 ` [PATCH 11/14] KVM: arm64: Expose kvm_pte_valid() helper Quentin Perret
2021-07-21 8:20 ` Fuad Tabba
2021-07-19 10:47 ` [PATCH 12/14] KVM: arm64: Refactor pkvm_pgtable locking Quentin Perret
2021-07-21 8:37 ` Fuad Tabba
2021-07-19 10:47 ` [PATCH 13/14] KVM: arm64: Restrict hyp stage-1 manipulation in protected mode Quentin Perret
2021-07-21 10:45 ` Fuad Tabba
2021-07-21 13:35 ` Quentin Perret
2021-07-19 10:47 ` [PATCH 14/14] KVM: arm64: Prevent late calls to __pkvm_create_private_mapping() Quentin Perret
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