Messages in this thread Patch in this message | | | Date | Mon, 28 Jul 2008 13:33:44 -0700 | From | Jeremy Fitzhardinge <> | Subject | Re: [PATCH] xen: fix allocation and use of large ldts |
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Ingo Molnar wrote: > * Jeremy Fitzhardinge <jeremy@goop.org> wrote: > > >> When the ldt gets to more than 1 page in size, the kernel uses vmalloc >> to allocate it. This means that: >> - when making the ldt RO, we must update the pages in both the vmalloc >> mapping and the linear mapping to make sure there are no RW aliases. >> - we need to use arbitrary_virt_to_machine to compute the machine addr >> for each update >> > > applied to tip/x86/xen, thanks Jeremy. >
Thanks. Here's a follow-up tidy patch.
Subject: xen: tidy up ldt fixes
Add a proper comment for set_aliased_prot() and fix an unsigned long/void * warning.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> --- arch/x86/xen/enlighten.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)
=================================================================== --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -395,8 +395,10 @@ } /* - * If 'v' is a vmalloc mapping, then find the linear mapping of the - * page (if any) and also set its protections to match: + * Set the page permissions for a particular virtual address. If the + * address is a vmalloc mapping (or other non-linear mapping), then + * find the linear mapping of the page and also set its protections to + * match. */ static void set_aliased_prot(void *v, pgprot_t prot) { @@ -545,8 +547,7 @@ static void xen_write_ldt_entry(struct desc_struct *dt, int entrynum, const void *ptr) { - unsigned long lp = (unsigned long)&dt[entrynum]; - xmaddr_t mach_lp = arbitrary_virt_to_machine(lp); + xmaddr_t mach_lp = arbitrary_virt_to_machine(&dt[entrynum]); u64 entry = *(u64 *)ptr; preempt_disable();
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