On Fri, 2013-07-26 at 11:16 +0530, Bharat Bhushan wrote:
> 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.
Why don't you do like server instead and enforce the use of the same I
and M bits as the corresponding qemu PTE ?
Cheers,
Ben.
> Signed-off-by: Bharat Bhushan <bharat.bhus...@freescale.com>
> ---
> 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);
>
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