[PATCH] x86/xen: Make virt_to_pfn() a static inline

[Linus Walleij]

Making virt_to_pfn() a static inline taking a strongly typed
(const void *) makes the contract of a passing a pointer of that
type to the function explicit and exposes any misuse of the
macro virt_to_pfn() acting polymorphic and accepting many types
such as (void *), (unitptr_t) or (unsigned long) as arguments
without warnings.

Also fix all offending call sites to pass a (void *) rather
than an unsigned long. Since virt_to_mfn() is wrapping
virt_to_pfn() this function has become polymorphic as well
so the usage need to be fixed up.

Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
---
 arch/x86/include/asm/xen/page.h |  5 ++++-
 arch/x86/xen/enlighten_pv.c     |  2 +-
 arch/x86/xen/mmu_pv.c           | 12 ++++++------
 arch/x86/xen/setup.c            |  4 ++--
 4 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h
index fa9ec20783fa..85e63d58c074 100644
--- a/arch/x86/include/asm/xen/page.h
+++ b/arch/x86/include/asm/xen/page.h
@@ -295,7 +295,10 @@ static inline unsigned long bfn_to_local_pfn(unsigned long mfn)
 
 /* VIRT <-> MACHINE conversion */
 #define virt_to_machine(v)	(phys_to_machine(XPADDR(__pa(v))))
-#define virt_to_pfn(v)          (PFN_DOWN(__pa(v)))
+static inline unsigned long virt_to_pfn(const void *v)
+{
+	return PFN_DOWN(__pa(v));
+}
 #define virt_to_mfn(v)		(pfn_to_mfn(virt_to_pfn(v)))
 #define mfn_to_virt(m)		(__va(mfn_to_pfn(m) << PAGE_SHIFT))
 
diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index 93b658248d01..7178976c5dcf 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -523,7 +523,7 @@ static void __init xen_load_gdt_boot(const struct desc_ptr *dtr)
 	BUG_ON(size > PAGE_SIZE);
 	BUG_ON(va & ~PAGE_MASK);
 
-	pfn = virt_to_pfn(va);
+	pfn = virt_to_pfn((void *)va);
 	mfn = pfn_to_mfn(pfn);
 
 	pte = pfn_pte(pfn, PAGE_KERNEL_RO);
diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c
index e0a975165de7..c4f20581f6e7 100644
--- a/arch/x86/xen/mmu_pv.c
+++ b/arch/x86/xen/mmu_pv.c
@@ -2202,13 +2202,13 @@ static void xen_zap_pfn_range(unsigned long vaddr, unsigned int order,
 		mcs = __xen_mc_entry(0);
 
 		if (in_frames)
-			in_frames[i] = virt_to_mfn(vaddr);
+			in_frames[i] = virt_to_mfn((void *)vaddr);
 
 		MULTI_update_va_mapping(mcs.mc, vaddr, VOID_PTE, 0);
-		__set_phys_to_machine(virt_to_pfn(vaddr), INVALID_P2M_ENTRY);
+		__set_phys_to_machine(virt_to_pfn((void *)vaddr), INVALID_P2M_ENTRY);
 
 		if (out_frames)
-			out_frames[i] = virt_to_pfn(vaddr);
+			out_frames[i] = virt_to_pfn((void *)vaddr);
 	}
 	xen_mc_issue(0);
 }
@@ -2250,7 +2250,7 @@ static void xen_remap_exchanged_ptes(unsigned long vaddr, int order,
 		MULTI_update_va_mapping(mcs.mc, vaddr,
 				mfn_pte(mfn, PAGE_KERNEL), flags);
 
-		set_phys_to_machine(virt_to_pfn(vaddr), mfn);
+		set_phys_to_machine(virt_to_pfn((void *)vaddr), mfn);
 	}
 
 	xen_mc_issue(0);
@@ -2327,7 +2327,7 @@ int xen_create_contiguous_region(phys_addr_t pstart, unsigned int order,
 	xen_zap_pfn_range(vstart, order, in_frames, NULL);
 
 	/* 2. Get a new contiguous memory extent. */
-	out_frame = virt_to_pfn(vstart);
+	out_frame = virt_to_pfn((void *)vstart);
 	success = xen_exchange_memory(1UL << order, 0, in_frames,
 				      1, order, &out_frame,
 				      address_bits);
@@ -2360,7 +2360,7 @@ void xen_destroy_contiguous_region(phys_addr_t pstart, unsigned int order)
 	spin_lock_irqsave(&xen_reservation_lock, flags);
 
 	/* 1. Find start MFN of contiguous extent. */
-	in_frame = virt_to_mfn(vstart);
+	in_frame = virt_to_mfn((void *)vstart);
 
 	/* 2. Zap current PTEs. */
 	xen_zap_pfn_range(vstart, order, NULL, out_frames);
diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index 8b5cf7bb1f47..50c998b844fb 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -340,7 +340,7 @@ static void __init xen_do_set_identity_and_remap_chunk(
 
 	WARN_ON(size == 0);
 
-	mfn_save = virt_to_mfn(buf);
+	mfn_save = virt_to_mfn((void *)buf);
 
 	for (ident_pfn_iter = start_pfn, remap_pfn_iter = remap_pfn;
 	     ident_pfn_iter < ident_end_pfn;
@@ -503,7 +503,7 @@ void __init xen_remap_memory(void)
 	unsigned long pfn_s = ~0UL;
 	unsigned long len = 0;
 
-	mfn_save = virt_to_mfn(buf);
+	mfn_save = virt_to_mfn((void *)buf);
 
 	while (xen_remap_mfn != INVALID_P2M_ENTRY) {
 		/* Map the remap information */

---
base-commit: 06c2afb862f9da8dc5efa4b6076a0e48c3fbaaa5
change-id: 20230808-virt-to-phys-x86-xen-1b7a69235a29

Best regards,
-- 
Linus Walleij <linus.walleij@xxxxxxxxxx>