Re: [PATCH kernel 2/9] KVM: PPC: Make real_vmalloc_addr() public

[David Gibson]

On Tue, Sep 15, 2015 at 08:49:32PM +1000, Alexey Kardashevskiy wrote:
> This helper translates vmalloc'd addresses to linear addresses.
> It is only used by the KVM MMU code now and resides in the HV KVM code.
> We will need it further in the TCE code and the DMA memory preregistration
> code called in real mode.
> 
> This makes real_vmalloc_addr() public and moves it to the powerpc code as
> it does not do anything special for KVM.
> 
> Signed-off-by: Alexey Kardashevskiy 

Hmm, I have a couple of small concerns.

First, I'm not sure if the name is clear enough for a public function.

Second, I'm not sure if mmu-hash64.h is the right place for it.  This
is still a function with very specific and limited usage, I wonder if
we should have somewhere else for such special real mode helpers.

Paulus, thoughts?

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David Gibson| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
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[PATCH kernel 2/9] KVM: PPC: Make real_vmalloc_addr() public

[Alexey Kardashevskiy]

This helper translates vmalloc'd addresses to linear addresses.
It is only used by the KVM MMU code now and resides in the HV KVM code.
We will need it further in the TCE code and the DMA memory preregistration
code called in real mode.

This makes real_vmalloc_addr() public and moves it to the powerpc code as
it does not do anything special for KVM.

Signed-off-by: Alexey Kardashevskiy 
---
 arch/powerpc/include/asm/mmu-hash64.h |  3 +++
 arch/powerpc/kvm/book3s_hv_rm_mmu.c   | 17 -
 arch/powerpc/mm/hash_utils_64.c   | 17 +
 3 files changed, 20 insertions(+), 17 deletions(-)

diff --git a/arch/powerpc/include/asm/mmu-hash64.h 
b/arch/powerpc/include/asm/mmu-hash64.h
index a82f534..fd06b73 100644
--- a/arch/powerpc/include/asm/mmu-hash64.h
+++ b/arch/powerpc/include/asm/mmu-hash64.h
@@ -606,6 +606,9 @@ static inline unsigned long get_kernel_vsid(unsigned long 
ea, int ssize)
context = (MAX_USER_CONTEXT) + ((ea >> 60) - 0xc) + 1;
return get_vsid(context, ea, ssize);
 }
+
+void *real_vmalloc_addr(void *x);
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* _ASM_POWERPC_MMU_HASH64_H_ */
diff --git a/arch/powerpc/kvm/book3s_hv_rm_mmu.c 
b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
index c1df9bb..987b7d1 100644
--- a/arch/powerpc/kvm/book3s_hv_rm_mmu.c
+++ b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
@@ -22,23 +22,6 @@
 #include 
 #include 
 
-/* Translate address of a vmalloc'd thing to a linear map address */
-static void *real_vmalloc_addr(void *x)
-{
-   unsigned long addr = (unsigned long) x;
-   pte_t *p;
-   /*
-* assume we don't have huge pages in vmalloc space...
-* So don't worry about THP collapse/split. Called
-* Only in realmode, hence won't need irq_save/restore.
-*/
-   p = __find_linux_pte_or_hugepte(swapper_pg_dir, addr, NULL);
-   if (!p || !pte_present(*p))
-   return NULL;
-   addr = (pte_pfn(*p) << PAGE_SHIFT) | (addr & ~PAGE_MASK);
-   return __va(addr);
-}
-
 /* Return 1 if we need to do a global tlbie, 0 if we can use tlbiel */
 static int global_invalidates(struct kvm *kvm, unsigned long flags)
 {
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 5ec987f..9737d6a 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -1556,3 +1556,20 @@ void setup_initial_memory_limit(phys_addr_t 
first_memblock_base,
/* Finally limit subsequent allocations */
memblock_set_current_limit(ppc64_rma_size);
 }
+
+/* Translate address of a vmalloc'd thing to a linear map address */
+void *real_vmalloc_addr(void *x)
+{
+   unsigned long addr = (unsigned long) x;
+   pte_t *p;
+   /*
+* assume we don't have huge pages in vmalloc space...
+* So don't worry about THP collapse/split. Called
+* Only in realmode, hence won't need irq_save/restore.
+*/
+   p = __find_linux_pte_or_hugepte(swapper_pg_dir, addr, NULL);
+   if (!p || !pte_present(*p))
+   return NULL;
+   addr = (pte_pfn(*p) << PAGE_SHIFT) | (addr & ~PAGE_MASK);
+   return __va(addr);
+}
-- 
2.4.0.rc3.8.gfb3e7d5

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