Messages in this thread Patch in this message | | | Date | Mon, 14 Jan 2008 09:04:06 -0800 | From | Jeremy Fitzhardinge <> | Subject | Re: [PATCH] adjust/fix LDT handling for Xen |
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Jan Beulich wrote: >>>> Ingo Molnar <mingo@elte.hu> 14.01.08 16:48 >>> >>>> >> * Jan Beulich <jbeulich@novell.com> wrote: >> >> >>> 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. >>> >> coul dyou try this against x86.git as well? We already unified ldt.c as >> part of the paravirt patches. >> > > Sure, but it may take me a little while.
I've got the unified version here.
Subject: xen: adjust/fix LDT handling for Xen
From: "Jan Beulich" <jbeulich@novell.com>
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.
[ Adjusted to unified ldt.c - Jeremy ]
Signed-off-by: Jan Beulich <jbeulich@novell.com> Acked-by: Jeremy Fitzhardinge <jeremy@xensource.com> Cc: Ingo Molnar <mingo@elte.hu>
--- arch/x86/kernel/ldt.c | 7 +++---- arch/x86/xen/enlighten.c | 9 +-------- 2 files changed, 4 insertions(+), 12 deletions(-)
=================================================================== --- a/arch/x86/kernel/ldt.c +++ b/arch/x86/kernel/ldt.c @@ -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> @@ -40,7 +39,7 @@ 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; @@ -78,7 +77,7 @@ 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; } @@ -129,7 +128,7 @@ 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; } } =================================================================== --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -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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