From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anthony Liguori Subject: Re: [PATCH 3/8] SVM: add module parameter to disable Nested Paging Date: Fri, 25 Jan 2008 15:35:23 -0600 Message-ID: <479A561B.8070009@codemonkey.ws> References: <1201294393-22613-1-git-send-email-joerg.roedel@amd.com> <1201294393-22613-4-git-send-email-joerg.roedel@amd.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Avi Kivity To: Joerg Roedel Return-path: In-Reply-To: <1201294393-22613-4-git-send-email-joerg.roedel-5C7GfCeVMHo@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org Joerg Roedel wrote: > To disable the use of the Nested Paging feature even if it is available in > hardware this patch adds a module parameter. Nested Paging can be disabled by > passing npt=off to the kvm_amd module. > > Signed-off-by: Joerg Roedel > --- > arch/x86/kvm/svm.c | 8 ++++++++ > 1 files changed, 8 insertions(+), 0 deletions(-) > > diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c > index 49bb57a..2e718ff 100644 > --- a/arch/x86/kvm/svm.c > +++ b/arch/x86/kvm/svm.c > @@ -48,6 +48,9 @@ MODULE_LICENSE("GPL"); > #define SVM_DEATURE_SVML (1 << 2) > > static bool npt_enabled = false; > +static char *npt = "on"; > + > +module_param(npt, charp, S_IRUGO); > This would probably be better as an integer. Then we don't have to do nasty things like implicitly cast a literal to a char *. Regards, Anthony Liguori > static void kvm_reput_irq(struct vcpu_svm *svm); > > @@ -415,6 +418,11 @@ static __init int svm_hardware_setup(void) > if (!svm_has(SVM_FEATURE_NPT)) > npt_enabled = false; > > + if (npt_enabled && strncmp(npt, "off", 3) == 0) { > + printk(KERN_INFO "kvm: Nested Paging disabled\n"); > + npt_enabled = false; > + } > + > if (npt_enabled) > printk(KERN_INFO "kvm: Nested Paging enabled\n"); > > ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/