From: Alok Kataria Date: Fri, 6 Feb 2009 18:29:35 +0000 (-0800) Subject: x86, vmi: put a missing paravirt_release_pmd in pgd_dtor X-Git-Tag: firefly_0821_release~15492^2~18 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=55a8ba4b7f76bebd7e8ce3f74c04b140627a1bad;p=firefly-linux-kernel-4.4.55.git x86, vmi: put a missing paravirt_release_pmd in pgd_dtor Commit 6194ba6ff6ccf8d5c54c857600843c67aa82c407 ("x86: don't special-case pmd allocations as much") made changes to the way we handle pmd allocations, and while doing that it dropped a call to paravirt_release_pd on the pgd page from the pgd_dtor code path. As a result of this missing release, the hypervisor is now unaware of the pgd page being freed, and as a result it ends up tracking this page as a page table page. After this the guest may start using the same page for other purposes, and depending on what use the page is put to, it may result in various performance and/or functional issues ( hangs, reboots). Since this release is only required for VMI, I now release the pgd page from the (vmi)_pgd_free hook. Signed-off-by: Alok N Kataria Acked-by: Jeremy Fitzhardinge Signed-off-by: Ingo Molnar Cc: --- diff --git a/arch/x86/kernel/vmi_32.c b/arch/x86/kernel/vmi_32.c index 1d3302cc2ddf..bef58b4982db 100644 --- a/arch/x86/kernel/vmi_32.c +++ b/arch/x86/kernel/vmi_32.c @@ -320,6 +320,16 @@ static void vmi_release_pmd(unsigned long pfn) vmi_ops.release_page(pfn, VMI_PAGE_L2); } +/* + * We use the pgd_free hook for releasing the pgd page: + */ +static void vmi_pgd_free(struct mm_struct *mm, pgd_t *pgd) +{ + unsigned long pfn = __pa(pgd) >> PAGE_SHIFT; + + vmi_ops.release_page(pfn, VMI_PAGE_L2); +} + /* * Helper macros for MMU update flags. We can defer updates until a flush * or page invalidation only if the update is to the current address space @@ -762,6 +772,7 @@ static inline int __init activate_vmi(void) if (vmi_ops.release_page) { pv_mmu_ops.release_pte = vmi_release_pte; pv_mmu_ops.release_pmd = vmi_release_pmd; + pv_mmu_ops.pgd_free = vmi_pgd_free; } /* Set linear is needed in all cases */