From 41f2e4771a4f1ba26c35438daf32917b9ef7858d Mon Sep 17 00:00:00 2001 From: Jeremy Fitzhardinge Date: Tue, 30 Mar 2010 11:47:40 -0700 Subject: xen: add support for PAT Convert Linux PAT entries into Xen ones when constructing ptes. Linux doesn't use _PAGE_PAT for ptes, so the only difference in the first 4 entries is that Linux uses _PAGE_PWT for WC, whereas Xen (and default) use it for WT. xen_pte_val does the inverse conversion. We hard-code assumptions about Linux's current PAT layout, but a warning on the wrmsr to MSR_IA32_CR_PAT should point out any problems. If necessary we could go to a more general table-based conversion between Linux and Xen PAT entries. hugetlbfs poses a problem at the moment, the x86 architecture uses the same flag for _PAGE_PAT and _PAGE_PSE, which changes meaning depending on which pagetable level we're using. At the moment this should be OK so long as nobody tries to do a pte_val on a hugetlbfs pte. Signed-off-by: Jeremy Fitzhardinge --- arch/x86/xen/enlighten.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'arch/x86/xen/enlighten.c') diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c index d8873014b5ed..b860e576ed0c 100644 --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -829,6 +829,11 @@ static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high) Xen console noise. */ break; + case MSR_IA32_CR_PAT: + if (smp_processor_id() == 0) + xen_set_pat(((u64)high << 32) | low); + break; + default: ret = native_write_msr_safe(msr, low, high); } -- cgit v1.2.3