Messages in this thread Patch in this message | | | Date | Fri, 11 Jan 2008 09:22:38 +0000 | From | "Jan Beulich" <> | Subject | [PATCH] adjust/fix LDT handling for Xen |
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Don't rely on kmalloc(PAGE_SIZE) returning PAGE_SIZE aligned memory (Xen requires GDT *and* LDT to be page-aligned). Using the page allocator interface also removes the (albeit small) slab allocator overhead. The same change being done for 64-bits for consistency.
Further, the Xen hypercall interface expects the LDT address to be virtual, not machine.
Signed-off-by: Jan Beulich <jbeulich@novell.com> Cc: Ingo Molnar <mingo@elte.hu>
--- arch/x86/kernel/ldt_32.c | 7 +++---- arch/x86/kernel/ldt_64.c | 7 +++---- arch/x86/xen/enlighten.c | 9 +-------- 3 files changed, 7 insertions(+), 16 deletions(-)
--- linux-2.6.24-rc7/arch/x86/kernel/ldt_32.c 2008-01-10 16:53:54.000000000 +0100 +++ 2.6.24-rc7-x86-xen-ldt/arch/x86/kernel/ldt_32.c 2008-01-09 13:59:50.000000000 +0100 @@ -9,7 +9,6 @@ #include <linux/mm.h> #include <linux/smp.h> #include <linux/vmalloc.h> -#include <linux/slab.h> #include <asm/uaccess.h> #include <asm/system.h> @@ -38,7 +37,7 @@ static int alloc_ldt(mm_context_t *pc, i if (mincount*LDT_ENTRY_SIZE > PAGE_SIZE) newldt = vmalloc(mincount*LDT_ENTRY_SIZE); else - newldt = kmalloc(mincount*LDT_ENTRY_SIZE, GFP_KERNEL); + newldt = (void *)__get_free_page(GFP_KERNEL); if (!newldt) return -ENOMEM; @@ -69,7 +68,7 @@ static int alloc_ldt(mm_context_t *pc, i if (oldsize*LDT_ENTRY_SIZE > PAGE_SIZE) vfree(oldldt); else - kfree(oldldt); + put_page(virt_to_page(oldldt)); } return 0; } @@ -114,7 +113,7 @@ void destroy_context(struct mm_struct *m if (mm->context.size*LDT_ENTRY_SIZE > PAGE_SIZE) vfree(mm->context.ldt); else - kfree(mm->context.ldt); + put_page(virt_to_page(mm->context.ldt)); mm->context.size = 0; } } --- linux-2.6.24-rc7/arch/x86/kernel/ldt_64.c 2008-01-10 16:53:54.000000000 +0100 +++ 2.6.24-rc7-x86-xen-ldt/arch/x86/kernel/ldt_64.c 2008-01-09 13:59:50.000000000 +0100 @@ -12,7 +12,6 @@ #include <linux/mm.h> #include <linux/smp.h> #include <linux/vmalloc.h> -#include <linux/slab.h> #include <asm/uaccess.h> #include <asm/system.h> @@ -41,7 +40,7 @@ static int alloc_ldt(mm_context_t *pc, u if (mincount*LDT_ENTRY_SIZE > PAGE_SIZE) newldt = vmalloc(mincount*LDT_ENTRY_SIZE); else - newldt = kmalloc(mincount*LDT_ENTRY_SIZE, GFP_KERNEL); + newldt = (void *)__get_free_page(GFP_KERNEL); if (!newldt) return -ENOMEM; @@ -73,7 +72,7 @@ static int alloc_ldt(mm_context_t *pc, u if (oldsize*LDT_ENTRY_SIZE > PAGE_SIZE) vfree(oldldt); else - kfree(oldldt); + put_page(virt_to_page(oldldt)); } return 0; } @@ -117,7 +116,7 @@ void destroy_context(struct mm_struct *m if ((unsigned)mm->context.size*LDT_ENTRY_SIZE > PAGE_SIZE) vfree(mm->context.ldt); else - kfree(mm->context.ldt); + put_page(virt_to_page(mm->context.ldt)); mm->context.size = 0; } } --- linux-2.6.24-rc7/arch/x86/xen/enlighten.c 2008-01-10 16:53:55.000000000 +0100 +++ 2.6.24-rc7-x86-xen-ldt/arch/x86/xen/enlighten.c 2008-01-09 14:00:51.000000000 +0100 @@ -275,19 +275,12 @@ static unsigned long xen_store_tr(void) static void xen_set_ldt(const void *addr, unsigned entries) { - unsigned long linear_addr = (unsigned long)addr; struct mmuext_op *op; struct multicall_space mcs = xen_mc_entry(sizeof(*op)); op = mcs.args; op->cmd = MMUEXT_SET_LDT; - if (linear_addr) { - /* ldt my be vmalloced, use arbitrary_virt_to_machine */ - xmaddr_t maddr; - maddr = arbitrary_virt_to_machine((unsigned long)addr); - linear_addr = (unsigned long)maddr.maddr; - } - op->arg1.linear_addr = linear_addr; + op->arg1.linear_addr = (unsigned long)addr; op->arg2.nr_ents = entries; MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
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