linux-kernel - [RFC PATCH 26/27] KVM: arm64: Sort the memblock regions list

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Message-Id: <20201117181607.1761516-27-qperret@google.com>
Date:   Tue, 17 Nov 2020 18:16:06 +0000
From:   Quentin Perret <qperret@...gle.com>
To:     Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>, Marc Zyngier <maz@...nel.org>,
        James Morse <james.morse@....com>,
        Julien Thierry <julien.thierry.kdev@...il.com>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Rob Herring <robh+dt@...nel.org>,
        Frank Rowand <frowand.list@...il.com>
Cc:     "moderated list:ARM64 PORT (AARCH64 ARCHITECTURE)" 
        <linux-arm-kernel@...ts.infradead.org>,
        open list <linux-kernel@...r.kernel.org>,
        "open list:KERNEL VIRTUAL MACHINE FOR ARM64 (KVM/arm64)" 
        <kvmarm@...ts.cs.columbia.edu>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE" 
        <devicetree@...r.kernel.org>, kernel-team@...roid.com,
        android-kvm@...gle.com, Quentin Perret <qperret@...gle.com>
Subject: [RFC PATCH 26/27] KVM: arm64: Sort the memblock regions list

The hypervisor will need the list of memblock regions sorted by
increasing start address to make look-ups more efficient. Make the
host do the hard work early while it is still trusted to avoid the need
for a sorting library at EL2.

Signed-off-by: Quentin Perret <qperret@...gle.com>
---
 arch/arm64/include/asm/kvm_host.h |  1 +
 arch/arm64/kvm/arm.c              |  1 +
 arch/arm64/kvm/hyp/reserved_mem.c | 18 ++++++++++++++++++
 3 files changed, 20 insertions(+)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 53b01d25e7d9..ec304a5c728b 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -746,6 +746,7 @@ bool kvm_arm_vcpu_is_finalized(struct kvm_vcpu *vcpu);
 extern phys_addr_t hyp_mem_base;
 extern phys_addr_t hyp_mem_size;
 void __init reserve_kvm_hyp(void);
+void kvm_sort_memblock_regions(void);
 #else
 static inline void reserve_kvm_hyp(void) { }
 #endif
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index e06c95a10dba..8160a0d12a58 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -1685,6 +1685,7 @@ static int kvm_hyp_enable_protection(void)
 		return ret;
 
 	kvm_set_hyp_vector();
+	kvm_sort_memblock_regions();
 	ret = kvm_call_hyp_nvhe(__kvm_hyp_protect, hyp_mem_base, hyp_mem_size,
 				num_possible_cpus(), kern_hyp_va(per_cpu_base));
 	if (ret)
diff --git a/arch/arm64/kvm/hyp/reserved_mem.c b/arch/arm64/kvm/hyp/reserved_mem.c
index c2c0484b6211..7da8e2915c1c 100644
--- a/arch/arm64/kvm/hyp/reserved_mem.c
+++ b/arch/arm64/kvm/hyp/reserved_mem.c
@@ -6,6 +6,7 @@
 
 #include <linux/kvm_host.h>
 #include <linux/memblock.h>
+#include <linux/sort.h>
 
 #include <asm/kvm_host.h>
 
@@ -31,6 +32,23 @@ void __init early_init_dt_add_memory_hyp(u64 base, u64 size)
 	kvm_nvhe_sym(hyp_memblock_nr)++;
 }
 
+static int cmp_hyp_memblock(const void *p1, const void *p2)
+{
+	const struct hyp_memblock_region *r1 = p1;
+	const struct hyp_memblock_region *r2 = p2;
+
+	return r1->start < r2->start ? -1 : (r1->start > r2->start);
+}
+
+void kvm_sort_memblock_regions(void)
+{
+	sort(kvm_nvhe_sym(hyp_memory),
+	     kvm_nvhe_sym(hyp_memblock_nr),
+	     sizeof(struct hyp_memblock_region),
+	     cmp_hyp_memblock,
+	     NULL);
+}
+
 extern bool enable_protected_kvm;
 void __init reserve_kvm_hyp(void)
 {
-- 
2.29.2.299.gdc1121823c-goog