From: Fuad Tabba <tabba@google.com>
To: Quentin Perret <qperret@google.com>
Cc: maz@kernel.org, james.morse@arm.com, alexandru.elisei@arm.com,
suzuki.poulose@arm.com, catalin.marinas@arm.com,
will@kernel.org, linux-arm-kernel@lists.infradead.org,
kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org,
ardb@kernel.org, qwandor@google.com, dbrazdil@google.com,
kernel-team@android.com
Subject: Re: [PATCH v3 03/21] KVM: arm64: Provide the host_stage2_try() helper macro
Date: Mon, 2 Aug 2021 11:36:42 +0200 [thread overview]
Message-ID: <CA+EHjTzrqbyHQyo7X-=MeJXQ5bVcfUz0uiUKVAv_U+aqVNuhYw@mail.gmail.com> (raw)
In-Reply-To: <20210729132818.4091769-4-qperret@google.com>
Hi Quentin.
On Thu, Jul 29, 2021 at 3:28 PM 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 | 40 +++++++++++++++------------
> 1 file changed, 22 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..74280a753efb 100644
> --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c
> +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
> @@ -208,6 +208,25 @@ 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.
> + */
The comment you added in V2 about host_kvm.lock got dropped in favor
asserting that the lock is held.
Reviewed-by: Fuad Tabba <tabba@google.com>
Thanks,
/fuad
> +#define host_stage2_try(fn, ...) \
> + ({ \
> + int __ret; \
> + hyp_assert_lock_held(&host_kvm.lock); \
> + __ret = fn(__VA_ARGS__); \
> + if (__ret == -ENOMEM) { \
> + __ret = host_stage2_unmap_dev_all(); \
> + if (!__ret) \
> + __ret = fn(__VA_ARGS__); \
> + } \
> + __ret; \
> + })
> +
> static int host_stage2_idmap(u64 addr)
> {
> enum kvm_pgtable_prot prot = KVM_PGTABLE_PROT_R | KVM_PGTABLE_PROT_W;
> @@ -223,22 +242,7 @@ 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 +261,8 @@ 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;
> --
> 2.32.0.432.gabb21c7263-goog
>
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next prev parent reply other threads:[~2021-08-02 9:39 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-29 13:27 [PATCH v3 00/21] Track shared pages at EL2 in protected mode Quentin Perret
2021-07-29 13:27 ` [PATCH v3 01/21] KVM: arm64: Add hyp_spin_is_locked() for basic locking assertions at EL2 Quentin Perret
2021-07-29 13:27 ` [PATCH v3 02/21] KVM: arm64: Introduce hyp_assert_lock_held() Quentin Perret
2021-07-29 13:28 ` [PATCH v3 03/21] KVM: arm64: Provide the host_stage2_try() helper macro Quentin Perret
2021-08-02 9:36 ` Fuad Tabba [this message]
2021-07-29 13:28 ` [PATCH v3 04/21] KVM: arm64: Introduce helper to retrieve a PTE and its level Quentin Perret
2021-07-29 13:28 ` [PATCH v3 05/21] KVM: arm64: Expose page-table helpers Quentin Perret
2021-07-29 13:28 ` [PATCH v3 06/21] KVM: arm64: Optimize host memory aborts Quentin Perret
2021-08-02 9:37 ` Fuad Tabba
2021-07-29 13:28 ` [PATCH v3 07/21] KVM: arm64: Rename KVM_PTE_LEAF_ATTR_S2_IGNORED Quentin Perret
2021-08-02 9:37 ` Fuad Tabba
2021-07-29 13:28 ` [PATCH v3 08/21] KVM: arm64: Don't overwrite software bits with owner id Quentin Perret
2021-08-02 9:38 ` Fuad Tabba
2021-07-29 13:28 ` [PATCH v3 09/21] KVM: arm64: Tolerate re-creating hyp mappings to set software bits Quentin Perret
2021-08-02 9:50 ` Fuad Tabba
2021-07-29 13:28 ` [PATCH v3 10/21] KVM: arm64: Enable forcing page-level stage-2 mappings Quentin Perret
2021-08-02 9:49 ` Fuad Tabba
2021-08-03 10:13 ` Quentin Perret
2021-08-03 10:43 ` Fuad Tabba
2021-07-29 13:28 ` [PATCH v3 11/21] KVM: arm64: Allow populating software bits Quentin Perret
2021-07-29 13:28 ` [PATCH v3 12/21] KVM: arm64: Add helpers to tag shared pages in SW bits Quentin Perret
2021-08-02 10:30 ` Fuad Tabba
2021-07-29 13:28 ` [PATCH v3 13/21] KVM: arm64: Expose host stage-2 manipulation helpers Quentin Perret
2021-08-02 11:13 ` Fuad Tabba
2021-08-03 10:20 ` Quentin Perret
2021-07-29 13:28 ` [PATCH v3 14/21] KVM: arm64: Expose pkvm_hyp_id Quentin Perret
2021-07-29 13:28 ` [PATCH v3 15/21] KVM: arm64: Introduce addr_is_memory() Quentin Perret
2021-08-02 14:52 ` Fuad Tabba
2021-08-03 10:23 ` Quentin Perret
2021-07-29 13:28 ` [PATCH v3 16/21] KVM: arm64: Enable retrieving protections attributes of PTEs Quentin Perret
2021-08-02 14:52 ` Fuad Tabba
2021-08-03 10:24 ` Quentin Perret
2021-07-29 13:28 ` [PATCH v3 17/21] KVM: arm64: Mark host bss and rodata section as shared Quentin Perret
2021-08-03 5:02 ` Fuad Tabba
2021-08-03 10:34 ` Quentin Perret
2021-08-03 10:54 ` Fuad Tabba
2021-07-29 13:28 ` [PATCH v3 18/21] KVM: arm64: Remove __pkvm_mark_hyp Quentin Perret
2021-07-29 13:28 ` [PATCH v3 19/21] KVM: arm64: Refactor protected nVHE stage-1 locking Quentin Perret
2021-08-03 5:31 ` Fuad Tabba
2021-08-03 10:37 ` Quentin Perret
2021-08-03 10:51 ` Fuad Tabba
2021-07-29 13:28 ` [PATCH v3 20/21] KVM: arm64: Restrict EL2 stage-1 changes in protected mode Quentin Perret
2021-08-03 8:22 ` Fuad Tabba
2021-08-03 10:43 ` Quentin Perret
2021-07-29 13:28 ` [PATCH v3 21/21] KVM: arm64: Make __pkvm_create_mappings static Quentin Perret
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