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From:   Keqian Zhu <zhukeqian1@huawei.com>
To:     <linux-kernel@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <kvmarm@lists.cs.columbia.edu>, <kvm@vger.kernel.org>
CC:     Catalin Marinas <catalin.marinas@arm.com>,
        Marc Zyngier <maz@kernel.org>,
        James Morse <james.morse@arm.com>,
        Will Deacon <will@kernel.org>,
        "Suzuki K Poulose" <suzuki.poulose@arm.com>,
        Sean Christopherson <sean.j.christopherson@intel.com>,
        Julien Thierry <julien.thierry.kdev@gmail.com>,
        Mark Brown <broonie@kernel.org>,
        "Thomas Gleixner" <tglx@linutronix.de>,
        Andrew Morton <akpm@linux-foundation.org>,
        Alexios Zavras <alexios.zavras@intel.com>,
        <wanghaibin.wang@huawei.com>, <zhengxiang9@huawei.com>,
        Keqian Zhu <zhukeqian1@huawei.com>,
        Peng Liang <liangpeng10@huawei.com>
Subject: [RFC PATCH 1/7] KVM: arm64: Add some basic functions for hw DBM
Date:   Mon, 25 May 2020 19:24:00 +0800
Message-ID: <20200525112406.28224-2-zhukeqian1@huawei.com>
In-Reply-To: <20200525112406.28224-1-zhukeqian1@huawei.com>
References: <20200525112406.28224-1-zhukeqian1@huawei.com>
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Prepare some basic functions used by following patches to support
hardware DBM.

Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com>
Signed-off-by: Peng Liang <liangpeng10@huawei.com>
---
 arch/arm64/include/asm/kvm_mmu.h | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
index 30b0e8d6b895..8df078f0ee67 100644
--- a/arch/arm64/include/asm/kvm_mmu.h
+++ b/arch/arm64/include/asm/kvm_mmu.h
@@ -285,6 +285,30 @@ static inline bool kvm_s2pud_young(pud_t pud)
 	return pud_young(pud);
 }
 
+#ifdef CONFIG_ARM64_HW_AFDBM
+static inline bool kvm_hw_dbm_enabled(void)
+{
+	return !!(read_sysreg(vtcr_el2) & VTCR_EL2_HD);
+}
+
+static inline void kvm_set_s2pte_dbm(pte_t *ptep)
+{
+	pteval_t old_pteval, pteval;
+
+	pteval = READ_ONCE(pte_val(*ptep));
+	do {
+		old_pteval = pteval;
+		pteval |= PTE_DBM;
+		pteval = cmpxchg_relaxed(&pte_val(*ptep), old_pteval, pteval);
+	} while (pteval != old_pteval);
+}
+
+static inline bool kvm_s2pte_dbm(pte_t *ptep)
+{
+	return !!(READ_ONCE(pte_val(*ptep)) & PTE_DBM);
+}
+#endif /* CONFIG_ARM64_HW_AFDBM */
+
 #define hyp_pte_table_empty(ptep) kvm_page_empty(ptep)
 
 #ifdef __PAGETABLE_PMD_FOLDED
-- 
2.19.1