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Subject[PATCH v9 6/8] KVM: arm64: Support handling access faults for PUD hugepages
Date
In preparation for creating larger hugepages at Stage 2, extend the
access fault handling at Stage 2 to support PUD hugepages when
encountered.

Provide trivial helpers for arm32 to allow sharing of code.

Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Christoffer Dall <christoffer.dall@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
---
arch/arm/include/asm/kvm_mmu.h | 9 +++++++++
arch/arm64/include/asm/kvm_mmu.h | 7 +++++++
arch/arm64/include/asm/pgtable.h | 6 ++++++
virt/kvm/arm/mmu.c | 22 +++++++++++-----------
4 files changed, 33 insertions(+), 11 deletions(-)

diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h
index 839a619873d3..fea5e723e3ac 100644
--- a/arch/arm/include/asm/kvm_mmu.h
+++ b/arch/arm/include/asm/kvm_mmu.h
@@ -85,6 +85,9 @@ void kvm_clear_hyp_idmap(void);
#define kvm_pfn_pte(pfn, prot) pfn_pte(pfn, prot)
#define kvm_pfn_pmd(pfn, prot) pfn_pmd(pfn, prot)

+#define kvm_pud_pfn(pud) ({ BUG(); 0; })
+
+
#define kvm_pmd_mkhuge(pmd) pmd_mkhuge(pmd)

/*
@@ -108,6 +111,12 @@ static inline bool kvm_s2pud_exec(pud_t *pud)
return false;
}

+static inline pud_t kvm_s2pud_mkyoung(pud_t pud)
+{
+ BUG();
+ return pud;
+}
+
static inline pte_t kvm_s2pte_mkwrite(pte_t pte)
{
pte_val(pte) |= L_PTE_S2_RDWR;
diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
index c755b37b3f92..612032bbb428 100644
--- a/arch/arm64/include/asm/kvm_mmu.h
+++ b/arch/arm64/include/asm/kvm_mmu.h
@@ -187,6 +187,8 @@ void kvm_clear_hyp_idmap(void);
#define kvm_pfn_pte(pfn, prot) pfn_pte(pfn, prot)
#define kvm_pfn_pmd(pfn, prot) pfn_pmd(pfn, prot)

+#define kvm_pud_pfn(pud) pud_pfn(pud)
+
#define kvm_pmd_mkhuge(pmd) pmd_mkhuge(pmd)

static inline pte_t kvm_s2pte_mkwrite(pte_t pte)
@@ -266,6 +268,11 @@ static inline bool kvm_s2pud_exec(pud_t *pudp)
return !(READ_ONCE(pud_val(*pudp)) & PUD_S2_XN);
}

+static inline pud_t kvm_s2pud_mkyoung(pud_t pud)
+{
+ return pud_mkyoung(pud);
+}
+
#define hyp_pte_table_empty(ptep) kvm_page_empty(ptep)

#ifdef __PAGETABLE_PMD_FOLDED
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 50b1ef8584c0..f51e2271e6a3 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -314,6 +314,11 @@ static inline pte_t pud_pte(pud_t pud)
return __pte(pud_val(pud));
}

+static inline pud_t pte_pud(pte_t pte)
+{
+ return __pud(pte_val(pte));
+}
+
static inline pmd_t pud_pmd(pud_t pud)
{
return __pmd(pud_val(pud));
@@ -381,6 +386,7 @@ static inline int pmd_protnone(pmd_t pmd)
#define pfn_pmd(pfn,prot) __pmd(__phys_to_pmd_val((phys_addr_t)(pfn) << PAGE_SHIFT) | pgprot_val(prot))
#define mk_pmd(page,prot) pfn_pmd(page_to_pfn(page),prot)

+#define pud_mkyoung(pud) pte_pud(pte_mkyoung(pud_pte(pud)))
#define pud_write(pud) pte_write(pud_pte(pud))

#define __pud_to_phys(pud) __pte_to_phys(pud_pte(pud))
diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c
index 8e44dccd1b47..bd749601195f 100644
--- a/virt/kvm/arm/mmu.c
+++ b/virt/kvm/arm/mmu.c
@@ -1698,6 +1698,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
*/
static void handle_access_fault(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa)
{
+ pud_t *pud;
pmd_t *pmd;
pte_t *pte;
kvm_pfn_t pfn;
@@ -1707,24 +1708,23 @@ static void handle_access_fault(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa)

spin_lock(&vcpu->kvm->mmu_lock);

- pmd = stage2_get_pmd(vcpu->kvm, NULL, fault_ipa);
- if (!pmd || pmd_none(*pmd)) /* Nothing there */
+ if (!stage2_get_leaf_entry(vcpu->kvm, fault_ipa, &pud, &pmd, &pte))
goto out;

- if (pmd_thp_or_huge(*pmd)) { /* THP, HugeTLB */
+ if (pud) { /* HugeTLB */
+ *pud = kvm_s2pud_mkyoung(*pud);
+ pfn = kvm_pud_pfn(*pud);
+ pfn_valid = true;
+ } else if (pmd) { /* THP, HugeTLB */
*pmd = pmd_mkyoung(*pmd);
pfn = pmd_pfn(*pmd);
pfn_valid = true;
- goto out;
+ } else {
+ *pte = pte_mkyoung(*pte); /* Just a page... */
+ pfn = pte_pfn(*pte);
+ pfn_valid = true;
}

- pte = pte_offset_kernel(pmd, fault_ipa);
- if (pte_none(*pte)) /* Nothing there either */
- goto out;
-
- *pte = pte_mkyoung(*pte); /* Just a page... */
- pfn = pte_pfn(*pte);
- pfn_valid = true;
out:
spin_unlock(&vcpu->kvm->mmu_lock);
if (pfn_valid)
--
2.19.1
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