kvm: arm64: Enable hardware updates of the Access Flag for Stage 2 page tables

[cascardo/linux.git] / arch / arm64 / include / asm / kvm_mmu.h

diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
index 249c4fc..844fe5d 100644 (file)
--- a/arch/arm64/include/asm/kvm_mmu.h
+++ b/arch/arm64/include/asm/kvm_mmu.h
@@ -111,19 +111,32 @@ static inline void kvm_clean_pmd_entry(pmd_t *pmd) {}
 static inline void kvm_clean_pte(pte_t *pte) {}
 static inline void kvm_clean_pte_entry(pte_t *pte) {}
 
-static inline void kvm_set_s2pte_writable(pte_t *pte)
+static inline pte_t kvm_s2pte_mkwrite(pte_t pte)
 {
-       pte_val(*pte) |= PTE_S2_RDWR;
+       pte_val(pte) |= PTE_S2_RDWR;
+       return pte;
 }
 
-static inline void kvm_set_s2pmd_writable(pmd_t *pmd)
+static inline pmd_t kvm_s2pmd_mkwrite(pmd_t pmd)
 {
-       pmd_val(*pmd) |= PMD_S2_RDWR;
+       pmd_val(pmd) |= PMD_S2_RDWR;
+       return pmd;
 }
 
 static inline void kvm_set_s2pte_readonly(pte_t *pte)
 {
-       pte_val(*pte) = (pte_val(*pte) & ~PTE_S2_RDWR) | PTE_S2_RDONLY;
+       pteval_t pteval;
+       unsigned long tmp;
+
+       asm volatile("//        kvm_set_s2pte_readonly\n"
+       "       prfm    pstl1strm, %2\n"
+       "1:     ldxr    %0, %2\n"
+       "       and     %0, %0, %3              // clear PTE_S2_RDWR\n"
+       "       orr     %0, %0, %4              // set PTE_S2_RDONLY\n"
+       "       stxr    %w1, %0, %2\n"
+       "       cbnz    %w1, 1b\n"
+       : "=&r" (pteval), "=&r" (tmp), "+Q" (pte_val(*pte))
+       : "L" (~PTE_S2_RDWR), "L" (PTE_S2_RDONLY));
 }
 
 static inline bool kvm_s2pte_readonly(pte_t *pte)
@@ -133,12 +146,12 @@ static inline bool kvm_s2pte_readonly(pte_t *pte)
 
 static inline void kvm_set_s2pmd_readonly(pmd_t *pmd)
 {
-       pmd_val(*pmd) = (pmd_val(*pmd) & ~PMD_S2_RDWR) | PMD_S2_RDONLY;
+       kvm_set_s2pte_readonly((pte_t *)pmd);
 }
 
 static inline bool kvm_s2pmd_readonly(pmd_t *pmd)
 {
-       return (pmd_val(*pmd) & PMD_S2_RDWR) == PMD_S2_RDONLY;
+       return kvm_s2pte_readonly((pte_t *)pmd);
 }
 
 static inline bool kvm_page_empty(void *ptr)