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Subject[PATCH v5 5/7] 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>
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 | 8 ++++++++
arch/arm64/include/asm/kvm_mmu.h | 7 +++++++
arch/arm64/include/asm/pgtable.h | 6 ++++++
virt/kvm/arm/mmu.c | 29 ++++++++++++++++-------------
4 files changed, 37 insertions(+), 13 deletions(-)

diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h
index d05c8986e495..a4298d429efc 100644
--- a/arch/arm/include/asm/kvm_mmu.h
+++ b/arch/arm/include/asm/kvm_mmu.h
@@ -78,6 +78,8 @@ 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_val(pud) & PUD_MASK) & PHYS_MASK) >> PAGE_SHIFT)
+
#define kvm_pmd_mkhuge(pmd) pmd_mkhuge(pmd)

/*
@@ -102,6 +104,12 @@ 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 void kvm_set_pmd(pmd_t *pmd, pmd_t new_pmd)
{
*pmd = new_pmd;
diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
index 15bc1be8f82f..4d2780c588b0 100644
--- a/arch/arm64/include/asm/kvm_mmu.h
+++ b/arch/arm64/include/asm/kvm_mmu.h
@@ -175,6 +175,8 @@ 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)
@@ -254,6 +256,11 @@ 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);
+}
+
static inline bool kvm_page_empty(void *ptr)
{
struct page *ptr_page = virt_to_page(ptr);
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 1bdeca8918a6..a64a5c35beb1 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));
@@ -380,6 +385,7 @@ 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 e73909a31e02..d2c705e31584 100644
--- a/virt/kvm/arm/mmu.c
+++ b/virt/kvm/arm/mmu.c
@@ -1637,33 +1637,36 @@ 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)
{
- pmd_t *pmd;
- pte_t *pte;
+ pud_t *pud = NULL;
+ pmd_t *pmd = NULL;
+ pte_t *pte = NULL;
kvm_pfn_t pfn;
- bool pfn_valid = false;
+ bool found, pfn_valid = false;

trace_kvm_access_fault(fault_ipa);

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

- pmd = stage2_get_pmd(vcpu->kvm, NULL, fault_ipa);
- if (!pmd || pmd_none(*pmd)) /* Nothing there */
+ found = stage2_get_leaf_entry(vcpu->kvm, fault_ipa, &pud, &pmd, &pte);
+ if (!found)
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;
+ goto out;
+ } 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)
--
2.17.1
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