linux-kernel - [PATCH v4 09/14] KVM: arm64: Introduce wrappers for host and hyp spin lock accessors

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Message-Id: <20211215161232.1480836-10-qperret@google.com>
Date:   Wed, 15 Dec 2021 16:12:26 +0000
From:   Quentin Perret <qperret@...gle.com>
To:     Marc Zyngier <maz@...nel.org>, James Morse <james.morse@....com>,
        Alexandru Elisei <alexandru.elisei@....com>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>
Cc:     qperret@...gle.com, qwandor@...gle.com,
        linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.cs.columbia.edu,
        linux-kernel@...r.kernel.org, kernel-team@...roid.com
Subject: [PATCH v4 09/14] KVM: arm64: Introduce wrappers for host and hyp spin
 lock accessors

From: Will Deacon <will@...nel.org>

In preparation for adding additional locked sections for manipulating
page-tables at EL2, introduce some simple wrappers around the host and
hypervisor locks so that it's a bit easier to read and bit more difficult
to take the wrong lock (or even take them in the wrong order).

Signed-off-by: Will Deacon <will@...nel.org>
Signed-off-by: Quentin Perret <qperret@...gle.com>
---
 arch/arm64/kvm/hyp/nvhe/mem_protect.c | 32 ++++++++++++++++++++++-----
 1 file changed, 26 insertions(+), 6 deletions(-)

diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
index 92262e89672d..907d3cbf1809 100644
--- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c
+++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
@@ -28,6 +28,26 @@ static struct hyp_pool host_s2_pool;
 
 const u8 pkvm_hyp_id = 1;
 
+static void host_lock_component(void)
+{
+	hyp_spin_lock(&host_kvm.lock);
+}
+
+static void host_unlock_component(void)
+{
+	hyp_spin_unlock(&host_kvm.lock);
+}
+
+static void hyp_lock_component(void)
+{
+	hyp_spin_lock(&pkvm_pgd_lock);
+}
+
+static void hyp_unlock_component(void)
+{
+	hyp_spin_unlock(&pkvm_pgd_lock);
+}
+
 static void *host_s2_zalloc_pages_exact(size_t size)
 {
 	void *addr = hyp_alloc_pages(&host_s2_pool, get_order(size));
@@ -339,14 +359,14 @@ static int host_stage2_idmap(u64 addr)
 
 	prot = is_memory ? PKVM_HOST_MEM_PROT : PKVM_HOST_MMIO_PROT;
 
-	hyp_spin_lock(&host_kvm.lock);
+	host_lock_component();
 	ret = host_stage2_adjust_range(addr, &range);
 	if (ret)
 		goto unlock;
 
 	ret = host_stage2_idmap_locked(range.start, range.end - range.start, prot);
 unlock:
-	hyp_spin_unlock(&host_kvm.lock);
+	host_unlock_component();
 
 	return ret;
 }
@@ -370,8 +390,8 @@ int __pkvm_host_share_hyp(u64 pfn)
 	if (!addr_is_memory(addr))
 		return -EINVAL;
 
-	hyp_spin_lock(&host_kvm.lock);
-	hyp_spin_lock(&pkvm_pgd_lock);
+	host_lock_component();
+	hyp_lock_component();
 
 	ret = kvm_pgtable_get_leaf(&host_kvm.pgt, addr, &pte, NULL);
 	if (ret)
@@ -433,8 +453,8 @@ int __pkvm_host_share_hyp(u64 pfn)
 	BUG_ON(ret);
 
 unlock:
-	hyp_spin_unlock(&pkvm_pgd_lock);
-	hyp_spin_unlock(&host_kvm.lock);
+	hyp_unlock_component();
+	host_unlock_component();
 
 	return ret;
 }
-- 
2.34.1.173.g76aa8bc2d0-goog