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kvm: arm64: Convert kvm_set_s2pte_readonly() from inline asm to cmpxchg() 

To take advantage of the LSE atomic instructions and also make the code
cleaner, convert the kvm_set_s2pte_readonly() function to use the more
generic cmpxchg().

Cc: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Catalin Marinas 2017-07-06 11:46:39 +01:00
parent 3bbf7157ac
commit 0966253d7c
1 changed files with 8 additions and 11 deletions
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19
arch/arm64/include/asm/kvm_mmu.h
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@ -175,18 +175,15 @@ static inline pmd_t kvm_s2pmd_mkwrite(pmd_t pmd)
static inline void kvm_set_s2pte_readonly(pte_t *pte)
{
pteval_t pteval;
unsigned long tmp;
pteval_t old_pteval, pteval;
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));
pteval = READ_ONCE(pte_val(*pte));
do {
old_pteval = pteval;
pteval &= ~PTE_S2_RDWR;
pteval |= PTE_S2_RDONLY;
pteval = cmpxchg_relaxed(&pte_val(*pte), old_pteval, pteval);
} while (pteval != old_pteval);
}
static inline bool kvm_s2pte_readonly(pte_t *pte)