If the page is RAM then map this as cacheable and coherent (set "M" bit)
otherwise this page is treated as I/O and map this as cache inhibited
and guarded (set "I + G")
This helps setting proper MMU mapping for direct assigned device.
NOTE: There can be devices that require cacheable mapping, which is not yet supported.
Signed-off-by: Bharat Bhushan <bharat.bhushan@xxxxxxxxxxxxx>
---
arch/powerpc/kvm/e500_mmu_host.c | 24 +++++++++++++++++++-----
1 files changed, 19 insertions(+), 5 deletions(-)
diff --git a/arch/powerpc/kvm/e500_mmu_host.c b/arch/powerpc/kvm/e500_mmu_host.c
index 1c6a9d7..5cbdc8f 100644
--- a/arch/powerpc/kvm/e500_mmu_host.c
+++ b/arch/powerpc/kvm/e500_mmu_host.c
@@ -64,13 +64,27 @@ static inline u32 e500_shadow_mas3_attrib(u32 mas3, int usermode)
return mas3;
}
-static inline u32 e500_shadow_mas2_attrib(u32 mas2, int usermode)
+static inline u32 e500_shadow_mas2_attrib(u32 mas2, pfn_t pfn)
{
+ u32 mas2_attr;
+
+ mas2_attr = mas2 & MAS2_ATTRIB_MASK;
+
+ if (kvm_is_mmio_pfn(pfn)) {
+ /*
+ * If page is not RAM then it is treated as I/O page.
+ * Map it with cache inhibited and guarded (set "I" + "G").
+ */
+ mas2_attr |= MAS2_I | MAS2_G;
+ return mas2_attr;
+ }
+
+ /* Map RAM pages as cacheable (Not setting "I" in MAS2) */
#ifdef CONFIG_SMP
- return (mas2 & MAS2_ATTRIB_MASK) | MAS2_M;
-#else
- return mas2 & MAS2_ATTRIB_MASK;
+ /* Also map as coherent (set "M") in SMP */
+ mas2_attr |= MAS2_M;
#endif
+ return mas2_attr;
}
/*
@@ -313,7 +327,7 @@ static void kvmppc_e500_setup_stlbe(
/* Force IPROT=0 for all guest mappings. */
stlbe->mas1 = MAS1_TSIZE(tsize) | get_tlb_sts(gtlbe) | MAS1_VALID;
stlbe->mas2 = (gvaddr & MAS2_EPN) |
- e500_shadow_mas2_attrib(gtlbe->mas2, pr);
+ e500_shadow_mas2_attrib(gtlbe->mas2, pfn);
stlbe->mas7_3 = ((u64)pfn << PAGE_SHIFT) |
e500_shadow_mas3_attrib(gtlbe->mas7_3, pr);
--
1.7.0.4
--
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