[Xen-devel] [PATCH v4 16/29] Ovmf/Xen: fix pointer to int cast in XenBusDxe

[Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>]

On ARM, xen_pfn_t is 64 bits but the size of a pointer is only
32 bits, so casting between them needs to go via (UINTN). Also
move the xen_pfn_t cast outside the shift so that we can avoid
shifting 64-bit quantities on 32-bit architectures, which may
require runtime library support.

Contributed-under: TianoCore Contribution Agreement 1.0
Reviewed-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
Reviewed-by: Laszlo Ersek <lersek@xxxxxxxxxx>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
---
 OvmfPkg/XenBusDxe/GrantTable.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/OvmfPkg/XenBusDxe/GrantTable.c b/OvmfPkg/XenBusDxe/GrantTable.c
index 37d3bf786c64..8405edc51bc4 100644
--- a/OvmfPkg/XenBusDxe/GrantTable.c
+++ b/OvmfPkg/XenBusDxe/GrantTable.c
@@ -160,7 +160,7 @@ XenGrantTableInit (
     Parameters.domid = DOMID_SELF;
     Parameters.idx = Index;
     Parameters.space = XENMAPSPACE_grant_table;
-    Parameters.gpfn = (((xen_pfn_t) GrantTable) >> EFI_PAGE_SHIFT) + Index;
+    Parameters.gpfn = (xen_pfn_t) ((UINTN) GrantTable >> EFI_PAGE_SHIFT) + 
Index;
     ReturnCode = XenHypercallMemoryOp (Dev, XENMEM_add_to_physmap, 
&Parameters);
     if (ReturnCode != 0) {
       DEBUG ((EFI_D_ERROR, "Xen GrantTable, add_to_physmap hypercall error: 
%d\n", ReturnCode));
@@ -182,7 +182,7 @@ XenGrantTableDeinit (
 
   for (Index = NR_GRANT_FRAMES - 1; Index >= 0; Index--) {
     Parameters.domid = DOMID_SELF;
-    Parameters.gpfn = (((xen_pfn_t) GrantTable) >> EFI_PAGE_SHIFT) + Index;
+    Parameters.gpfn = (xen_pfn_t) ((UINTN) GrantTable >> EFI_PAGE_SHIFT) + 
Index;
     DEBUG ((EFI_D_INFO, "Xen GrantTable, removing %X\n", Parameters.gpfn));
     ReturnCode = XenHypercallMemoryOp (Dev, XENMEM_remove_from_physmap, 
&Parameters);
     if (ReturnCode != 0) {
-- 
1.8.3.2


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