Hi Alejandro,
On 17/07/2023 17:03, Alejandro Vallejo wrote:
This patch factors out the pdx compression logic hardcoded in both ports
for the maddr<->vaddr conversion functions.
Touches both x86 and arm ports.
Signed-off-by: Alejandro Vallejo <alejandro.vall...@cloud.com>
---
xen/arch/arm/include/asm/mm.h | 3 +--
xen/arch/x86/include/asm/x86_64/page.h | 28 +++++++++++---------------
xen/include/xen/pdx.h | 25 +++++++++++++++++++++++
3 files changed, 38 insertions(+), 18 deletions(-)
diff --git a/xen/arch/arm/include/asm/mm.h b/xen/arch/arm/include/asm/mm.h
index 1a83f41879..78cb23858a 100644
--- a/xen/arch/arm/include/asm/mm.h
+++ b/xen/arch/arm/include/asm/mm.h
@@ -320,8 +320,7 @@ static inline void *maddr_to_virt(paddr_t ma)
(DIRECTMAP_SIZE >> PAGE_SHIFT));
return (void *)(XENHEAP_VIRT_START -
(directmap_base_pdx << PAGE_SHIFT) +
- ((ma & ma_va_bottom_mask) |
- ((ma & ma_top_mask) >> pfn_pdx_hole_shift)));
+ maddr_to_directmapoff(ma));
}
#endif
diff --git a/xen/arch/x86/include/asm/x86_64/page.h b/xen/arch/x86/include/asm/x86_64/page.h
index 53faa7875b..b589c93e77 100644
--- a/xen/arch/x86/include/asm/x86_64/page.h
+++ b/xen/arch/x86/include/asm/x86_64/page.h
@@ -36,26 +36,22 @@ static inline unsigned long __virt_to_maddr(unsigned long
va)
{
ASSERT(va < DIRECTMAP_VIRT_END);
if ( va >= DIRECTMAP_VIRT_START )
- va -= DIRECTMAP_VIRT_START;
- else
- {
- BUILD_BUG_ON(XEN_VIRT_END - XEN_VIRT_START != GB(1));
- /* Signed, so ((long)XEN_VIRT_START >> 30) fits in an imm32. */
- ASSERT(((long)va >> (PAGE_ORDER_1G + PAGE_SHIFT)) ==
- ((long)XEN_VIRT_START >> (PAGE_ORDER_1G + PAGE_SHIFT)));
-
- va += xen_phys_start - XEN_VIRT_START;
- }
- return (va & ma_va_bottom_mask) |
- ((va << pfn_pdx_hole_shift) & ma_top_mask);
+ return directmapoff_to_maddr(va - DIRECTMAP_VIRT_START);
+
+ BUILD_BUG_ON(XEN_VIRT_END - XEN_VIRT_START != GB(1));
+ /* Signed, so ((long)XEN_VIRT_START >> 30) fits in an imm32. */
+ ASSERT(((long)va >> (PAGE_ORDER_1G + PAGE_SHIFT)) ==
+ ((long)XEN_VIRT_START >> (PAGE_ORDER_1G + PAGE_SHIFT)));
+
+ return xen_phys_start + va - XEN_VIRT_START;
}
static inline void *__maddr_to_virt(unsigned long ma)
{
- ASSERT(pfn_to_pdx(ma >> PAGE_SHIFT) < (DIRECTMAP_SIZE >> PAGE_SHIFT));
- return (void *)(DIRECTMAP_VIRT_START +
- ((ma & ma_va_bottom_mask) |
- ((ma & ma_top_mask) >> pfn_pdx_hole_shift)));
+ /* Offset in the direct map, accounting for pdx compression */
+ size_t va_offset = maddr_to_directmapoff(ma);
+ ASSERT(va_offset < DIRECTMAP_SIZE);
+ return (void *)(DIRECTMAP_VIRT_START + va_offset);
}
/* read access (should only be used for debug printk's) */
diff --git a/xen/include/xen/pdx.h b/xen/include/xen/pdx.h
index 67ae20e89c..f8ca0f5821 100644
--- a/xen/include/xen/pdx.h
+++ b/xen/include/xen/pdx.h
@@ -158,6 +158,31 @@ static inline unsigned long pdx_to_pfn(unsigned long pdx)
#define mfn_to_pdx(mfn) pfn_to_pdx(mfn_x(mfn))
#define pdx_to_mfn(pdx) _mfn(pdx_to_pfn(pdx))
+/**
+ * Computes the offset into the direct map of an maddr
+ *
+ * @param ma Machine address
+ * @return Offset on the direct map where that
+ * machine address can be accessed
+ */
+static inline unsigned long maddr_to_directmapoff(uint64_t ma)
+{
+ return ((ma & ma_top_mask) >> pfn_pdx_hole_shift) |
+ (ma & ma_va_bottom_mask);
NIT: I got a bit confused because your re-order the two operations. I
guess this was done because it is nicer to read.
Anyway, I have confirmed the logic is still the same (just different
ordering).
+}
+
+/**
+ * Computes a machine address given a direct map offset
+ *
+ * @param offset Offset into the direct map
+ * @return Corresponding machine address of that virtual location
+ */
+static inline uint64_t directmapoff_to_maddr(unsigned long offset)
+{
+ return ((offset << pfn_pdx_hole_shift) & ma_top_mask) |
'unsigned long' may be 32-bit. So I think you want to cast offset to
uint64_t.
Cheers,
--
Julien Grall
