ple_window is updated on every vmentry, so there is no reason to have it read-only anymore. ple_window* weren't writable to prevent runtime overflow races; they are prevented by a seqlock.
Signed-off-by: Radim Krčmář <rkrc...@redhat.com> --- arch/x86/kvm/vmx.c | 48 +++++++++++++++++++++++++++++++++++++----------- 1 file changed, 37 insertions(+), 11 deletions(-) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index f63ac5d..bd73fa1 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -132,24 +132,29 @@ module_param(nested, bool, S_IRUGO); #define KVM_VMX_DEFAULT_PLE_WINDOW_MAX \ INT_MAX / KVM_VMX_DEFAULT_PLE_WINDOW_GROW +static struct kernel_param_ops param_ops_ple_t; +#define param_check_ple_t(name, p) __param_check(name, p, int) + +static DEFINE_SEQLOCK(ple_window_seqlock); + static int ple_gap = KVM_VMX_DEFAULT_PLE_GAP; module_param(ple_gap, int, S_IRUGO); static int ple_window = KVM_VMX_DEFAULT_PLE_WINDOW; -module_param(ple_window, int, S_IRUGO); +module_param(ple_window, ple_t, S_IRUGO | S_IWUSR); /* Default doubles per-vcpu window every exit. */ static int ple_window_grow = KVM_VMX_DEFAULT_PLE_WINDOW_GROW; -module_param(ple_window_grow, int, S_IRUGO); +module_param(ple_window_grow, ple_t, S_IRUGO | S_IWUSR); /* Default resets per-vcpu window every exit to ple_window. */ static int ple_window_shrink = KVM_VMX_DEFAULT_PLE_WINDOW_SHRINK; -module_param(ple_window_shrink, int, S_IRUGO); +module_param(ple_window_shrink, int, S_IRUGO | S_IWUSR); /* Default is to compute the maximum so we can never overflow. */ static int ple_window_actual_max = KVM_VMX_DEFAULT_PLE_WINDOW_MAX; static int ple_window_max = KVM_VMX_DEFAULT_PLE_WINDOW_MAX; -module_param(ple_window_max, int, S_IRUGO); +module_param(ple_window_max, ple_t, S_IRUGO | S_IWUSR); extern const ulong vmx_return; @@ -5730,13 +5735,19 @@ static void modify_ple_window(struct kvm_vcpu *vcpu, int grow) struct vcpu_vmx *vmx = to_vmx(vcpu); int old = vmx->ple_window; int new; + unsigned seq; - if (grow) - new = __grow_ple_window(old) - else - new = __shrink_ple_window(old, ple_window_shrink, ple_window); + do { + seq = read_seqbegin(&ple_window_seqlock); - vmx->ple_window = max(new, ple_window); + if (grow) + new = __grow_ple_window(old); + else + new = __shrink_ple_window(old, ple_window_shrink, + ple_window); + + vmx->ple_window = max(new, ple_window); + } while (read_seqretry(&ple_window_seqlock, seq)); trace_kvm_ple_window(grow, vcpu->vcpu_id, vmx->ple_window, old); } @@ -5750,6 +5761,23 @@ static void update_ple_window_actual_max(void) ple_window_grow, INT_MIN); } +static int param_set_ple_t(const char *arg, const struct kernel_param *kp) +{ + int ret; + + write_seqlock(&ple_window_seqlock); + ret = param_set_int(arg, kp); + update_ple_window_actual_max(); + write_sequnlock(&ple_window_seqlock); + + return ret; +} + +static struct kernel_param_ops param_ops_ple_t = { + .set = param_set_ple_t, + .get = param_get_int, +}; + /* * Indicate a busy-waiting vcpu in spinlock. We do not enable the PAUSE * exiting, so only get here on cpu with PAUSE-Loop-Exiting. @@ -9153,8 +9181,6 @@ static int __init vmx_init(void) } else kvm_disable_tdp(); - update_ple_window_actual_max(); - return 0; out7: -- 2.0.4 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html