diff options
| -rw-r--r-- | arch/x86/xen/enlighten.c | 5 | ||||
| -rw-r--r-- | arch/x86/xen/mmu.c | 53 | ||||
| -rw-r--r-- | arch/x86/xen/xen-ops.h | 2 |
3 files changed, 57 insertions, 3 deletions
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c index d8873014b5e..b860e576ed0 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); } diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c index b2371671b11..67b41017f7b 100644 --- a/arch/x86/xen/mmu.c +++ b/arch/x86/xen/mmu.c @@ -55,6 +55,7 @@ #include <asm/e820.h> #include <asm/linkage.h> #include <asm/page.h> +#include <asm/pat.h> #include <asm/xen/hypercall.h> #include <asm/xen/hypervisor.h> @@ -780,10 +781,18 @@ static pteval_t iomap_pte(pteval_t val) pteval_t xen_pte_val(pte_t pte) { - if (xen_initial_domain() && (pte.pte & _PAGE_IOMAP)) - return pte.pte; + pteval_t pteval = pte.pte; - return pte_mfn_to_pfn(pte.pte); + /* 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; + } + + if (xen_initial_domain() && (pteval & _PAGE_IOMAP)) + return pteval; + + return pte_mfn_to_pfn(pteval); } PV_CALLEE_SAVE_REGS_THUNK(xen_pte_val); @@ -793,10 +802,48 @@ 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- UC UC- + * 7 PAT PCD PWT UC UC 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); +} + pte_t xen_make_pte(pteval_t pte) { phys_addr_t addr = (pte & PTE_PFN_MASK); + /* 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; + } + /* * Unprivileged domains are allowed to do IOMAPpings for * PCI passthrough, but not map ISA space. The ISA diff --git a/arch/x86/xen/xen-ops.h b/arch/x86/xen/xen-ops.h index d505e98e03f..64044747348 100644 --- a/arch/x86/xen/xen-ops.h +++ b/arch/x86/xen/xen-ops.h @@ -32,6 +32,8 @@ void xen_ident_map_ISA(void); void xen_reserve_top(void); extern unsigned long xen_max_p2m_pfn; +void xen_set_pat(u64); + char * __init xen_memory_setup(void); void __init xen_arch_setup(void); void __init xen_init_IRQ(void); |