Re: [PATCH v2 2/4] KVM: arm/arm64: Introduce helpers to manupulate page table entries

From: Suzuki K Poulose
Date: Tue May 01 2018 - 06:36:43 EST


On 01/05/18 11:26, Punit Agrawal wrote:
Introduce helpers to abstract architectural handling of the conversion
of pfn to page table entries and marking a PMD page table entry as a
block entry.

The helpers are introduced in preparation for supporting PUD hugepages
at stage 2 - which are supported on arm64 but do not exist on arm.

Punit,

The change are fine by me. However, we usually do not define kvm_*
accessors for something which we know matches with the host variant.
i.e, PMD and PTE helpers, which are always present and we make use
of them directly. (see unmap_stage2_pmds for e.g)

Cheers
Suzuki


Signed-off-by: Punit Agrawal <punit.agrawal@xxxxxxx>
Acked-by: Christoffer Dall <christoffer.dall@xxxxxxx>
Cc: Marc Zyngier <marc.zyngier@xxxxxxx>
Cc: Russell King <linux@xxxxxxxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
---
arch/arm/include/asm/kvm_mmu.h | 5 +++++
arch/arm64/include/asm/kvm_mmu.h | 5 +++++
virt/kvm/arm/mmu.c | 7 ++++---
3 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h
index 707a1f06dc5d..5907a81ad5c1 100644
--- a/arch/arm/include/asm/kvm_mmu.h
+++ b/arch/arm/include/asm/kvm_mmu.h
@@ -75,6 +75,11 @@ phys_addr_t kvm_get_idmap_vector(void);
int kvm_mmu_init(void);
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_pmd_mkhuge(pmd) pmd_mkhuge(pmd)
+
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 082110993647..d962508ce4b3 100644
--- a/arch/arm64/include/asm/kvm_mmu.h
+++ b/arch/arm64/include/asm/kvm_mmu.h
@@ -173,6 +173,11 @@ void kvm_clear_hyp_idmap(void);
#define kvm_set_pte(ptep, pte) set_pte(ptep, pte)
#define kvm_set_pmd(pmdp, pmd) set_pmd(pmdp, pmd)
+#define kvm_pfn_pte(pfn, prot) pfn_pte(pfn, prot)
+#define kvm_pfn_pmd(pfn, prot) pfn_pmd(pfn, prot)
+
+#define kvm_pmd_mkhuge(pmd) pmd_mkhuge(pmd)
+
static inline pte_t kvm_s2pte_mkwrite(pte_t pte)
{
pte_val(pte) |= PTE_S2_RDWR;
diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c
index 686fc6a4b866..74750236f445 100644
--- a/virt/kvm/arm/mmu.c
+++ b/virt/kvm/arm/mmu.c
@@ -1554,8 +1554,9 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
invalidate_icache_guest_page(pfn, vma_pagesize);
if (hugetlb) {
- pmd_t new_pmd = pfn_pmd(pfn, mem_type);
- new_pmd = pmd_mkhuge(new_pmd);
+ pmd_t new_pmd = kvm_pfn_pmd(pfn, mem_type);
+
+ new_pmd = kvm_pmd_mkhuge(new_pmd);
if (writable)
new_pmd = kvm_s2pmd_mkwrite(new_pmd);
@@ -1564,7 +1565,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
ret = stage2_set_pmd_huge(kvm, memcache, fault_ipa, &new_pmd);
} else {
- pte_t new_pte = pfn_pte(pfn, mem_type);
+ pte_t new_pte = kvm_pfn_pte(pfn, mem_type);
if (writable) {
new_pte = kvm_s2pte_mkwrite(new_pte);