From 47591df505129c9774af6cca2debf283a6e56ed7 Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Mon, 3 Nov 2014 14:02:04 +0100 Subject: [PATCH] xen: Support Xen pv-domains using PAT With the dynamical mapping between cache modes and pgprot values it is now possible to use all cache modes via the Xen hypervisor PAT settings in a pv domain. All to be done is to read the PAT configuration MSR and set up the translation tables accordingly. Signed-off-by: Juergen Gross Reviewed-by: David Vrabel Reviewed-by: Konrad Rzeszutek Wilk Reviewed-by: Thomas Gleixner Cc: stefan.bader@canonical.com Cc: xen-devel@lists.xensource.com Cc: ville.syrjala@linux.intel.com Cc: jbeulich@suse.com Cc: toshi.kani@hp.com Cc: plagnioj@jcrosoft.com Cc: tomi.valkeinen@ti.com Cc: bhelgaas@google.com Link: http://lkml.kernel.org/r/1415019724-4317-19-git-send-email-jgross@suse.com Signed-off-by: Thomas Gleixner --- arch/x86/xen/enlighten.c | 25 ++++++--------------- arch/x86/xen/mmu.c | 47 +--------------------------------------- arch/x86/xen/xen-ops.h | 1 - 3 files changed, 8 insertions(+), 65 deletions(-) diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c index fac5e4f9607c..6bf3a13e3e0f 100644 --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -1100,12 +1100,6 @@ static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high) /* Fast syscall setup is all done in hypercalls, so these are all ignored. Stub them out here to stop 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); @@ -1561,10 +1555,6 @@ asmlinkage __visible void __init xen_start_kernel(void) /* Prevent unwanted bits from being set in PTEs. */ __supported_pte_mask &= ~_PAGE_GLOBAL; -#if 0 - if (!xen_initial_domain()) -#endif - __supported_pte_mask &= ~(_PAGE_PWT | _PAGE_PCD); /* * Prevent page tables from being allocated in highmem, even @@ -1617,14 +1607,6 @@ asmlinkage __visible void __init xen_start_kernel(void) * be meaningless. Prevent it from trying. */ acpi_numa = -1; -#endif -#ifdef CONFIG_X86_PAT - /* - * For right now disable the PAT. We should remove this once - * git commit 8eaffa67b43e99ae581622c5133e20b0f48bcef1 - * (xen/pat: Disable PAT support for now) is reverted. - */ - pat_enabled = 0; #endif /* Don't do the full vcpu_info placement stuff until we have a possible map and a non-dummy shared_info. */ @@ -1636,6 +1618,13 @@ asmlinkage __visible void __init xen_start_kernel(void) xen_raw_console_write("mapping kernel into physical memory\n"); xen_setup_kernel_pagetable((pgd_t *)xen_start_info->pt_base, xen_start_info->nr_pages); + /* + * Modify the cache mode translation tables to match Xen's PAT + * configuration. + */ + + pat_init_cache_modes(); + /* keep using Xen gdt for now; no urgent need to change it */ #ifdef CONFIG_X86_32 diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c index a8a1a3d08d4d..9855eb8ee4b3 100644 --- a/arch/x86/xen/mmu.c +++ b/arch/x86/xen/mmu.c @@ -410,13 +410,7 @@ static pteval_t pte_pfn_to_mfn(pteval_t val) __visible pteval_t xen_pte_val(pte_t pte) { pteval_t pteval = pte.pte; -#if 0 - /* If this is a WC pte, convert back from Xen WC to Linux WC */ - if ((pteval & (_PAGE_PAT | _PAGE_PCD | _PAGE_PWT)) == _PAGE_PAT) { - WARN_ON(!pat_enabled); - pteval = (pteval & ~_PAGE_PAT) | _PAGE_PWT; - } -#endif + return pte_mfn_to_pfn(pteval); } PV_CALLEE_SAVE_REGS_THUNK(xen_pte_val); @@ -427,47 +421,8 @@ __visible pgdval_t xen_pgd_val(pgd_t pgd) } PV_CALLEE_SAVE_REGS_THUNK(xen_pgd_val); -/* - * Xen's PAT setup is part of its ABI, though I assume entries 6 & 7 - * are reserved for now, to correspond to the Intel-reserved PAT - * types. - * - * We expect Linux's PAT set as follows: - * - * Idx PTE flags Linux Xen Default - * 0 WB WB WB - * 1 PWT WC WT WT - * 2 PCD UC- UC- UC- - * 3 PCD PWT UC UC UC - * 4 PAT WB WC WB - * 5 PAT PWT WC WP WT - * 6 PAT PCD UC- rsv UC- - * 7 PAT PCD PWT UC rsv UC - */ - -void xen_set_pat(u64 pat) -{ - /* We expect Linux to use a PAT setting of - * UC UC- WC WB (ignoring the PAT flag) */ - WARN_ON(pat != 0x0007010600070106ull); -} - __visible pte_t xen_make_pte(pteval_t pte) { -#if 0 - /* If Linux is trying to set a WC pte, then map to the Xen WC. - * If _PAGE_PAT is set, then it probably means it is really - * _PAGE_PSE, so avoid fiddling with the PAT mapping and hope - * things work out OK... - * - * (We should never see kernel mappings with _PAGE_PSE set, - * but we could see hugetlbfs mappings, I think.). - */ - if (pat_enabled && !WARN_ON(pte & _PAGE_PAT)) { - if ((pte & (_PAGE_PCD | _PAGE_PWT)) == _PAGE_PWT) - pte = (pte & ~(_PAGE_PCD | _PAGE_PWT)) | _PAGE_PAT; - } -#endif pte = pte_pfn_to_mfn(pte); return native_make_pte(pte); diff --git a/arch/x86/xen/xen-ops.h b/arch/x86/xen/xen-ops.h index 28c7e0be56e4..4ab9298c5e17 100644 --- a/arch/x86/xen/xen-ops.h +++ b/arch/x86/xen/xen-ops.h @@ -33,7 +33,6 @@ extern unsigned long xen_max_p2m_pfn; void xen_mm_pin_all(void); void xen_mm_unpin_all(void); -void xen_set_pat(u64); char * __init xen_memory_setup(void); char * xen_auto_xlated_memory_setup(void); -- 2.20.1