From patchwork Thu Aug 29 10:22:08 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexander Graf X-Patchwork-Id: 270761 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id D7B112C00C4 for ; Thu, 29 Aug 2013 20:22:45 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753601Ab3H2KWZ (ORCPT ); Thu, 29 Aug 2013 06:22:25 -0400 Received: from cantor2.suse.de ([195.135.220.15]:49850 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756057Ab3H2KWV (ORCPT ); Thu, 29 Aug 2013 06:22:21 -0400 Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 11491A51BB; Thu, 29 Aug 2013 12:22:20 +0200 (CEST) From: Alexander Graf To: kvm-ppc@vger.kernel.org Cc: "kvm@vger.kernel.org mailing list" , Paolo Bonzini , Gleb Natapov , Paul Mackerras Subject: [PULL 10/17] KVM: PPC: Book3S PR: Load up SPRG3 register with guest value on guest entry Date: Thu, 29 Aug 2013 12:22:08 +0200 Message-Id: <1377771735-3289-11-git-send-email-agraf@suse.de> X-Mailer: git-send-email 1.8.1.4 In-Reply-To: <1377771735-3289-1-git-send-email-agraf@suse.de> References: <1377771735-3289-1-git-send-email-agraf@suse.de> Sender: kvm-ppc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm-ppc@vger.kernel.org From: Paul Mackerras Unlike the other general-purpose SPRs, SPRG3 can be read by usermode code, and is used in recent kernels to store the CPU and NUMA node numbers so that they can be read by VDSO functions. Thus we need to load the guest's SPRG3 value into the real SPRG3 register when entering the guest, and restore the host's value when exiting the guest. We don't need to save the guest SPRG3 value when exiting the guest as usermode code can't modify SPRG3. Signed-off-by: Paul Mackerras Signed-off-by: Alexander Graf --- arch/powerpc/kernel/asm-offsets.c | 1 + arch/powerpc/kvm/book3s_interrupts.S | 14 ++++++++++++++ 2 files changed, 15 insertions(+) diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c index 6f16ffa..a67c76e 100644 --- a/arch/powerpc/kernel/asm-offsets.c +++ b/arch/powerpc/kernel/asm-offsets.c @@ -452,6 +452,7 @@ int main(void) DEFINE(VCPU_SPRG2, offsetof(struct kvm_vcpu, arch.shregs.sprg2)); DEFINE(VCPU_SPRG3, offsetof(struct kvm_vcpu, arch.shregs.sprg3)); #endif + DEFINE(VCPU_SHARED_SPRG3, offsetof(struct kvm_vcpu_arch_shared, sprg3)); DEFINE(VCPU_SHARED_SPRG4, offsetof(struct kvm_vcpu_arch_shared, sprg4)); DEFINE(VCPU_SHARED_SPRG5, offsetof(struct kvm_vcpu_arch_shared, sprg5)); DEFINE(VCPU_SHARED_SPRG6, offsetof(struct kvm_vcpu_arch_shared, sprg6)); diff --git a/arch/powerpc/kvm/book3s_interrupts.S b/arch/powerpc/kvm/book3s_interrupts.S index 48cbbf8..17cfae5 100644 --- a/arch/powerpc/kvm/book3s_interrupts.S +++ b/arch/powerpc/kvm/book3s_interrupts.S @@ -92,6 +92,11 @@ kvm_start_lightweight: PPC_LL r3, VCPU_HFLAGS(r4) rldicl r3, r3, 0, 63 /* r3 &= 1 */ stb r3, HSTATE_RESTORE_HID5(r13) + + /* Load up guest SPRG3 value, since it's user readable */ + ld r3, VCPU_SHARED(r4) + ld r3, VCPU_SHARED_SPRG3(r3) + mtspr SPRN_SPRG3, r3 #endif /* CONFIG_PPC_BOOK3S_64 */ PPC_LL r4, VCPU_SHADOW_MSR(r4) /* get shadow_msr */ @@ -123,6 +128,15 @@ kvmppc_handler_highmem: /* R7 = vcpu */ PPC_LL r7, GPR4(r1) +#ifdef CONFIG_PPC_BOOK3S_64 + /* + * Reload kernel SPRG3 value. + * No need to save guest value as usermode can't modify SPRG3. + */ + ld r3, PACA_SPRG3(r13) + mtspr SPRN_SPRG3, r3 +#endif /* CONFIG_PPC_BOOK3S_64 */ + PPC_STL r14, VCPU_GPR(R14)(r7) PPC_STL r15, VCPU_GPR(R15)(r7) PPC_STL r16, VCPU_GPR(R16)(r7)