[PATCH v5 5/7] KVM: arm64: Support handling access faults for PUD hugepages
From: Suzuki.Poulose@arm.com (Suzuki K Poulose)
Date: 2018-07-11 13:17:03
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kvmarm, lkml
On 09/07/18 15:41, Punit Agrawal wrote:
quoted hunk ↗ jump to hunk
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 <redacted> Cc: Christoffer Dall <redacted> Cc: Marc Zyngier <redacted> Cc: Russell King <linux@armlinux.org.uk> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <redacted> --- 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)
Since we don't have PUD in arm32, it would be good to trigger a BUG() instead of silently doing something wrong.
quoted hunk ↗ jump to hunk
@@ -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; +} +
Like this. ^
quoted hunk ↗ jump to hunk
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;
nit: You could use pfn_valid instead of a new "found" variable.
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;You don't need these goto's and the out lable anymore.
+ } 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)Otherwise look good to me. Suzuki