Thread (20 messages) 20 messages, 3 authors, 2021-08-11

Re: [PATCH 1/5] KVM: arm64: Drop direct PAGE_[SHIFT|SIZE] usage as page size

From: Marc Zyngier <maz@kernel.org>
Date: 2021-08-10 13:33:22
Also in: kvmarm, lkml

On 2021-08-10 08:02, Anshuman Khandual wrote:
quoted hunk ↗ jump to hunk
All instances here could just directly test against 
CONFIG_ARM64_XXK_PAGES
instead of evaluating via PAGE_SHIFT or PAGE_SIZE. With this change, 
there
will be no such usage left.

Cc: Marc Zyngier <maz@kernel.org>
Cc: James Morse <james.morse@arm.com>
Cc: Alexandru Elisei <redacted>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: kvmarm@lists.cs.columbia.edu
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Anshuman Khandual <redacted>
---
 arch/arm64/kvm/hyp/pgtable.c | 6 +++---
 arch/arm64/mm/mmu.c          | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/arch/arm64/kvm/hyp/pgtable.c 
b/arch/arm64/kvm/hyp/pgtable.c
index 05321f4165e3..a6112b6d6ef6 100644
--- a/arch/arm64/kvm/hyp/pgtable.c
+++ b/arch/arm64/kvm/hyp/pgtable.c
@@ -85,7 +85,7 @@ static bool kvm_level_supports_block_mapping(u32 
level)
 	 * Reject invalid block mappings and don't bother with 4TB mappings 
for
 	 * 52-bit PAs.
 	 */
-	return !(level == 0 || (PAGE_SIZE != SZ_4K && level == 1));
+	return !(level == 0 || (!IS_ENABLED(CONFIG_ARM64_4K_PAGES) && level 
== 1));
 }

 static bool kvm_block_mapping_supported(u64 addr, u64 end, u64 phys, 
u32 level)
@@ -155,7 +155,7 @@ static u64 kvm_pte_to_phys(kvm_pte_t pte)
 {
 	u64 pa = pte & KVM_PTE_ADDR_MASK;

-	if (PAGE_SHIFT == 16)
+	if (IS_ENABLED(CONFIG_ARM64_64K_PAGES))
 		pa |= FIELD_GET(KVM_PTE_ADDR_51_48, pte) << 48;

 	return pa;
@@ -165,7 +165,7 @@ static kvm_pte_t kvm_phys_to_pte(u64 pa)
 {
 	kvm_pte_t pte = pa & KVM_PTE_ADDR_MASK;

-	if (PAGE_SHIFT == 16)
+	if (IS_ENABLED(CONFIG_ARM64_64K_PAGES))
 		pte |= FIELD_PREP(KVM_PTE_ADDR_51_48, pa >> 48);

 	return pte;
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 9ff0de1b2b93..8fdfca179815 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -296,7 +296,7 @@ static void alloc_init_cont_pmd(pud_t *pudp,
unsigned long addr,
 static inline bool use_1G_block(unsigned long addr, unsigned long 
next,
 			unsigned long phys)
 {
-	if (PAGE_SHIFT != 12)
+	if (!IS_ENABLED(CONFIG_ARM64_4K_PAGES))
 		return false;

 	if (((addr | next | phys) & ~PUD_MASK) != 0)
I personally find it a lot less readable.

Also, there is no evaluation whatsoever. All the code guarded
by a PAGE_SIZE/PAGE_SHIFT that doesn't match the configuration
is dropped at compile time.

Thanks,

         M.
-- 
Jazz is not dead. It just smells funny...

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