On 07/18/2013 03:12 PM, Bhushan Bharat-R65777 wrote:
-----Original Message-----
From: "“tiejun.chen”" [mailto:tiejun.chen@xxxxxxxxxxxxx]
Sent: Thursday, July 18, 2013 11:56 AM
To: Bhushan Bharat-R65777
Cc: kvm-ppc@xxxxxxxxxxxxxxx; kvm@xxxxxxxxxxxxxxx; agraf@xxxxxxx; Wood Scott-
B07421; Bhushan Bharat-R65777
Subject: Re: [PATCH 2/2] kvm: powerpc: set cache coherency only for kernel
managed pages
On 07/18/2013 02:04 PM, Bharat Bhushan wrote:
If there is a struct page for the requested mapping then it's normal
DDR and the mapping sets "M" bit (coherent, cacheable) else this is
treated as I/O and we set "I + G" (cache inhibited, guarded)
This helps setting proper TLB mapping for direct assigned device
Signed-off-by: Bharat Bhushan <bharat.bhushan@xxxxxxxxxxxxx>
---
arch/powerpc/kvm/e500_mmu_host.c | 17 ++++++++++++-----
1 files changed, 12 insertions(+), 5 deletions(-)
diff --git a/arch/powerpc/kvm/e500_mmu_host.c
b/arch/powerpc/kvm/e500_mmu_host.c
index 1c6a9d7..089c227 100644
--- a/arch/powerpc/kvm/e500_mmu_host.c
+++ b/arch/powerpc/kvm/e500_mmu_host.c
@@ -64,13 +64,20 @@ 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 (!pfn_valid(pfn)) {
Why not directly use kvm_is_mmio_pfn()?
What I understand from this function (someone can correct me) is that it returns "false" when the page is managed by kernel and is not marked as RESERVED (for some reason). For us it does not matter whether the page is reserved or not, if it is kernel visible page then it is DDR.
I think you are setting I|G by addressing all mmio pages, right? If so,
KVM: direct mmio pfn check
Userspace may specify memory slots that are backed by mmio pages rather than
normal RAM. In some cases it is not enough to identify these mmio pages
by pfn_valid(). This patch adds checking the PageReserved as well.
Tiejun
-Bharat
Tiejun
+ mas2_attr |= MAS2_I | MAS2_G;
+ } else {
#ifdef CONFIG_SMP
- return (mas2 & MAS2_ATTRIB_MASK) | MAS2_M;
-#else
- return mas2 & MAS2_ATTRIB_MASK;
+ mas2_attr |= MAS2_M;
#endif
+ }
+ return mas2_attr;
}
/*
@@ -313,7 +320,7 @@ 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);
--
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