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From: Will Deacon <will@kernel.org>
To: kvmarm@lists.cs.columbia.edu
Cc: Will Deacon <will@kernel.org>,
	maz@kernel.org, kernel-team@android.com,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH 1/3] KVM: arm64: Don't free memcache pages in kvm_phys_addr_ioremap()
Date: Thu, 23 Jul 2020 12:02:25 +0100
Message-ID: <20200723110227.16001-2-will@kernel.org> (raw)
In-Reply-To: <20200723110227.16001-1-will@kernel.org>

kvm_phys_addr_ioremap() unconditionally empties out the memcache pages
for the current vCPU on return. This causes subsequent topups to allocate
fresh pages and is at odds with the behaviour when mapping memory in
user_mem_abort().

Remove the call to mmu_free_memory_cache() from kvm_phys_addr_ioremap(),
allowing the cached pages to be used by a later mapping.

Cc: Marc Zyngier <maz@kernel.org>
Cc: Quentin Perret <qperret@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
---
 arch/arm64/kvm/mmu.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 31058e6e7c2a..9102373a9744 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -1484,19 +1484,17 @@ int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa,
 					     kvm_mmu_cache_min_pages(kvm),
 					     KVM_NR_MEM_OBJS);
 		if (ret)
-			goto out;
+			break;
 		spin_lock(&kvm->mmu_lock);
 		ret = stage2_set_pte(kvm, &cache, addr, &pte,
 						KVM_S2PTE_FLAG_IS_IOMAP);
 		spin_unlock(&kvm->mmu_lock);
 		if (ret)
-			goto out;
+			break;
 
 		pfn++;
 	}
 
-out:
-	mmu_free_memory_cache(&cache);
 	return ret;
 }
 
-- 
2.28.0.rc0.105.gf9edc3c819-goog

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Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-23 11:02 [PATCH 0/3] KVM: arm64: Clean up memcache usage for page-table pages Will Deacon
2020-07-23 11:02 ` Will Deacon [this message]
2020-07-23 11:02 ` [PATCH 2/3] KVM: arm64: Simplify mmu_topup_memory_cache() Will Deacon
2020-07-23 11:02 ` [PATCH 3/3] KVM: arm64: Remove mmu_free_memory_cache() Will Deacon
2020-07-27  8:45 ` [PATCH 0/3] KVM: arm64: Clean up memcache usage for page-table pages Marc Zyngier
2020-07-27 10:38   ` Will Deacon

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