diff options
| author | Sean Christopherson <seanjc@google.com> | 2021-03-05 03:16:37 +0100 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2021-03-05 14:33:15 +0100 |
| commit | 99840a75454b66d69d2a450ab04e6438d75eba48 (patch) | |
| tree | 572c8e408b2e4791aaca75e5bea734566e52c194 /arch | |
| parent | KVM: x86: Ensure deadline timer has truly expired before posting its IRQ (diff) | |
| download | linux-99840a75454b66d69d2a450ab04e6438d75eba48.tar.xz linux-99840a75454b66d69d2a450ab04e6438d75eba48.zip | |
KVM: SVM: Connect 'npt' module param to KVM's internal 'npt_enabled'
Directly connect the 'npt' param to the 'npt_enabled' variable so that
runtime adjustments to npt_enabled are reflected in sysfs. Move the
!PAE restriction to a runtime check to ensure NPT is forced off if the
host is using 2-level paging, and add a comment explicitly stating why
NPT requires a 64-bit kernel or a kernel with PAE enabled.
Opportunistically switch the param to octal permissions.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210305021637.3768573-1-seanjc@google.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kvm/svm/svm.c | 25 |
1 files changed, 13 insertions, 12 deletions
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index baee91c1e936..58a45bb139f8 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -115,13 +115,6 @@ static const struct svm_direct_access_msrs { { .index = MSR_INVALID, .always = false }, }; -/* enable NPT for AMD64 and X86 with PAE */ -#if defined(CONFIG_X86_64) || defined(CONFIG_X86_PAE) -bool npt_enabled = true; -#else -bool npt_enabled; -#endif - /* * These 2 parameters are used to config the controls for Pause-Loop Exiting: * pause_filter_count: On processors that support Pause filtering(indicated @@ -170,9 +163,12 @@ module_param(pause_filter_count_shrink, ushort, 0444); static unsigned short pause_filter_count_max = KVM_SVM_DEFAULT_PLE_WINDOW_MAX; module_param(pause_filter_count_max, ushort, 0444); -/* allow nested paging (virtualized MMU) for all guests */ -static int npt = true; -module_param(npt, int, S_IRUGO); +/* + * Use nested page tables by default. Note, NPT may get forced off by + * svm_hardware_setup() if it's unsupported by hardware or the host kernel. + */ +bool npt_enabled = true; +module_param_named(npt, npt_enabled, bool, 0444); /* allow nested virtualization in KVM/SVM */ static int nested = true; @@ -988,10 +984,15 @@ static __init int svm_hardware_setup(void) goto err; } - if (!boot_cpu_has(X86_FEATURE_NPT)) + /* + * KVM's MMU doesn't support using 2-level paging for itself, and thus + * NPT isn't supported if the host is using 2-level paging since host + * CR4 is unchanged on VMRUN. + */ + if (!IS_ENABLED(CONFIG_X86_64) && !IS_ENABLED(CONFIG_X86_PAE)) npt_enabled = false; - if (npt_enabled && !npt) + if (!boot_cpu_has(X86_FEATURE_NPT)) npt_enabled = false; kvm_configure_mmu(npt_enabled, get_max_npt_level(), PG_LEVEL_1G); |