Date:   Wed, 15 Dec 2021 16:12:18 +0000
In-Reply-To: <20211215161232.1480836-1-qperret@google.com>
Message-Id: <20211215161232.1480836-2-qperret@google.com>
Mime-Version: 1.0
References: <20211215161232.1480836-1-qperret@google.com>
Subject: [PATCH v4 01/14] KVM: arm64: Provide {get,put}_page() stubs for early
 hyp allocator
From:   Quentin Perret <qperret@google.com>
To:     Marc Zyngier <maz@kernel.org>, James Morse <james.morse@arm.com>,
        Alexandru Elisei <alexandru.elisei@arm.com>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>
Cc:     qperret@google.com, qwandor@google.com,
        linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu,
        linux-kernel@vger.kernel.org, kernel-team@android.com
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

In nVHE protected mode, the EL2 code uses a temporary allocator during
boot while re-creating its stage-1 page-table. Unfortunately, the
hyp_vmmemap is not ready to use at this stage, so refcounting pages
is not possible. That is not currently a problem because hyp stage-1
mappings are never removed, which implies refcounting of page-table
pages is unnecessary.

In preparation for allowing hypervisor stage-1 mappings to be removed,
provide stub implementations for {get,put}_page() in the early allocator.

Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
---
 arch/arm64/kvm/hyp/nvhe/early_alloc.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/arm64/kvm/hyp/nvhe/early_alloc.c b/arch/arm64/kvm/hyp/nvhe/early_alloc.c
index 1306c430ab87..00de04153cc6 100644
--- a/arch/arm64/kvm/hyp/nvhe/early_alloc.c
+++ b/arch/arm64/kvm/hyp/nvhe/early_alloc.c
@@ -43,6 +43,9 @@ void *hyp_early_alloc_page(void *arg)
 	return hyp_early_alloc_contig(1);
 }
 
+static void hyp_early_alloc_get_page(void *addr) { }
+static void hyp_early_alloc_put_page(void *addr) { }
+
 void hyp_early_alloc_init(void *virt, unsigned long size)
 {
 	base = cur = (unsigned long)virt;
@@ -51,4 +54,6 @@ void hyp_early_alloc_init(void *virt, unsigned long size)
 	hyp_early_alloc_mm_ops.zalloc_page = hyp_early_alloc_page;
 	hyp_early_alloc_mm_ops.phys_to_virt = hyp_phys_to_virt;
 	hyp_early_alloc_mm_ops.virt_to_phys = hyp_virt_to_phys;
+	hyp_early_alloc_mm_ops.get_page = hyp_early_alloc_get_page;
+	hyp_early_alloc_mm_ops.put_page = hyp_early_alloc_put_page;
 }
-- 
2.34.1.173.g76aa8bc2d0-goog