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authorJuergen Gross <jgross@suse.com>2017-05-10 06:08:44 +0200
committerJuergen Gross <jgross@suse.com>2017-05-11 15:55:20 +0200
commit69861e0a52f8733355ce246f0db15e1b240ad667 (patch)
treeda511147606697a15f627492178a46c7d3643323
parentx86/amd: don't set X86_BUG_SYSRET_SS_ATTRS when running under Xen (diff)
downloadlinux-dev-69861e0a52f8733355ce246f0db15e1b240ad667.tar.xz
linux-dev-69861e0a52f8733355ce246f0db15e1b240ad667.zip
xen: adjust early dom0 p2m handling to xen hypervisor behavior
When booted as pv-guest the p2m list presented by the Xen is already mapped to virtual addresses. In dom0 case the hypervisor might make use of 2M- or 1G-pages for this mapping. Unfortunately while being properly aligned in virtual and machine address space, those pages might not be aligned properly in guest physical address space. So when trying to obtain the guest physical address of such a page pud_pfn() and pmd_pfn() must be avoided as those will mask away guest physical address bits not being zero in this special case. Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> Signed-off-by: Juergen Gross <jgross@suse.com>
-rw-r--r--arch/x86/xen/mmu_pv.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c
index 9d9ae6650aa1..7397d8b8459d 100644
--- a/arch/x86/xen/mmu_pv.c
+++ b/arch/x86/xen/mmu_pv.c
@@ -2025,7 +2025,8 @@ static unsigned long __init xen_read_phys_ulong(phys_addr_t addr)
/*
* Translate a virtual address to a physical one without relying on mapped
- * page tables.
+ * page tables. Don't rely on big pages being aligned in (guest) physical
+ * space!
*/
static phys_addr_t __init xen_early_virt_to_phys(unsigned long vaddr)
{
@@ -2046,7 +2047,7 @@ static phys_addr_t __init xen_early_virt_to_phys(unsigned long vaddr)
sizeof(pud)));
if (!pud_present(pud))
return 0;
- pa = pud_pfn(pud) << PAGE_SHIFT;
+ pa = pud_val(pud) & PTE_PFN_MASK;
if (pud_large(pud))
return pa + (vaddr & ~PUD_MASK);
@@ -2054,7 +2055,7 @@ static phys_addr_t __init xen_early_virt_to_phys(unsigned long vaddr)
sizeof(pmd)));
if (!pmd_present(pmd))
return 0;
- pa = pmd_pfn(pmd) << PAGE_SHIFT;
+ pa = pmd_val(pmd) & PTE_PFN_MASK;
if (pmd_large(pmd))
return pa + (vaddr & ~PMD_MASK);