[PATCH v9 3/8] KVM: arm/arm64: Introduce helpers to manipulate page table entries

From: Punit Agrawal
Date: Wed Oct 31 2018 - 13:58:28 EST


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.

Signed-off-by: Punit Agrawal <punit.agrawal@xxxxxxx>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@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 | 14 ++++++++------
3 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h
index 1098ffc3d54b..e6eff8bf5d7f 100644
--- a/arch/arm/include/asm/kvm_mmu.h
+++ b/arch/arm/include/asm/kvm_mmu.h
@@ -82,6 +82,11 @@ void kvm_clear_hyp_idmap(void);
#define kvm_mk_pud(pmdp) __pud(__pa(pmdp) | PMD_TYPE_TABLE)
#define kvm_mk_pgd(pudp) ({ BUILD_BUG(); 0; })

+#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) |= L_PTE_S2_RDWR;
diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
index 658657367f2f..13d482710292 100644
--- a/arch/arm64/include/asm/kvm_mmu.h
+++ b/arch/arm64/include/asm/kvm_mmu.h
@@ -184,6 +184,11 @@ void kvm_clear_hyp_idmap(void);
#define kvm_mk_pgd(pudp) \
__pgd(__phys_to_pgd_val(__pa(pudp)) | PUD_TYPE_TABLE)

+#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 6912529946fb..fb5325f7a1ac 100644
--- a/virt/kvm/arm/mmu.c
+++ b/virt/kvm/arm/mmu.c
@@ -607,7 +607,7 @@ static void create_hyp_pte_mappings(pmd_t *pmd, unsigned long start,
addr = start;
do {
pte = pte_offset_kernel(pmd, addr);
- kvm_set_pte(pte, pfn_pte(pfn, prot));
+ kvm_set_pte(pte, kvm_pfn_pte(pfn, prot));
get_page(virt_to_page(pte));
pfn++;
} while (addr += PAGE_SIZE, addr != end);
@@ -1202,7 +1202,7 @@ int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa,
pfn = __phys_to_pfn(pa);

for (addr = guest_ipa; addr < end; addr += PAGE_SIZE) {
- pte_t pte = pfn_pte(pfn, PAGE_S2_DEVICE);
+ pte_t pte = kvm_pfn_pte(pfn, PAGE_S2_DEVICE);

if (writable)
pte = kvm_s2pte_mkwrite(pte);
@@ -1611,8 +1611,10 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
(fault_status == FSC_PERM && stage2_is_exec(kvm, fault_ipa));

if (vma_pagesize == PMD_SIZE) {
- 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);

@@ -1621,7 +1623,7 @@ 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);
@@ -1878,7 +1880,7 @@ void kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte)
* just like a translation fault and clean the cache to the PoC.
*/
clean_dcache_guest_page(pfn, PAGE_SIZE);
- stage2_pte = pfn_pte(pfn, PAGE_S2);
+ stage2_pte = kvm_pfn_pte(pfn, PAGE_S2);
handle_hva_to_gpa(kvm, hva, end, &kvm_set_spte_handler, &stage2_pte);
}

--
2.19.1