Re: [PATCH v2 04/16] KVM: arm64: Optimize host memory aborts
From: Marc Zyngier <maz@kernel.org>
Date: 2021-07-26 13:24:48
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kvmarm, lkml
On Mon, 26 Jul 2021 14:13:06 +0100, Quentin Perret [off-list ref] wrote:
On Monday 26 Jul 2021 at 11:35:10 (+0100), Marc Zyngier wrote:
[...]
quoted hunk ↗ jump to hunk
quoted
You could also use a kvm_mem_range for the iteration, and add a helper that checks for the inclusion.Something like this (untested)?diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c index 75273166d2c5..07d228163090 100644 --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c@@ -234,9 +234,15 @@ static inline int __host_stage2_idmap(u64 start, u64 end, __ret; \ }) +static inline bool range_included(struct kvm_mem_range *child, + struct kvm_mem_range *parent) +{ + return parent->start <= child->start && child->end <= parent->end; +} + static int host_stage2_find_range(u64 addr, struct kvm_mem_range *range) { - u64 granule, start, end; + struct kvm_mem_range cur; kvm_pte_t pte; u32 level; int ret;@@ -252,16 +258,15 @@ static int host_stage2_find_range(u64 addr, struct kvm_mem_range *range) return -EPERM; do { - granule = kvm_granule_size(level); - start = ALIGN_DOWN(addr, granule); - end = start + granule; + u64 granule = kvm_granule_size(level); + cur.start = ALIGN_DOWN(addr, granule); + cur.end = cur.start + granule; level++; } while ((level < KVM_PGTABLE_MAX_LEVELS) && - (!kvm_level_supports_block_mapping(level) || - start < range->start || range->end < end)); + !(kvm_level_supports_block_mapping(level) && + range_included(&cur, parent))); - range->start = start; - range->end = end; + *range = cur; return 0; }
Beautiful. M. -- Without deviation from the norm, progress is not possible. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel