From: Paul Mackerras <paulus@samba.org> To: Alexander Graf <agraf@suse.de> Cc: kvm-ppc@vger.kernel.org, kvm@vger.kernel.org Subject: [PATCH 1/8] KVM: PPC: Book3S PR: Load up SPRG3 register with guest value on guest entry Date: Thu, 11 Jul 2013 21:49:43 +1000 [thread overview] Message-ID: <20130711114943.GC21353@iris.ozlabs.ibm.com> (raw) In-Reply-To: <20130711114839.GB21353@iris.ozlabs.ibm.com> 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 <paulus@samba.org> --- 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) -- 1.8.3.1
WARNING: multiple messages have this Message-ID (diff)
From: Paul Mackerras <paulus@samba.org> To: Alexander Graf <agraf@suse.de> Cc: kvm-ppc@vger.kernel.org, kvm@vger.kernel.org Subject: [PATCH 1/8] KVM: PPC: Book3S PR: Load up SPRG3 register with guest value on guest entry Date: Thu, 11 Jul 2013 11:49:43 +0000 [thread overview] Message-ID: <20130711114943.GC21353@iris.ozlabs.ibm.com> (raw) In-Reply-To: <20130711114839.GB21353@iris.ozlabs.ibm.com> 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 <paulus@samba.org> --- 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) -- 1.8.3.1
next prev parent reply other threads:[~2013-07-11 11:49 UTC|newest] Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top 2013-07-11 11:48 [PATCH 0/8] PR KVM fixes and improvements Paul Mackerras 2013-07-11 11:48 ` Paul Mackerras 2013-07-11 11:49 ` Paul Mackerras [this message] 2013-07-11 11:49 ` [PATCH 1/8] KVM: PPC: Book3S PR: Load up SPRG3 register with guest value on guest entry Paul Mackerras 2013-07-25 13:38 ` Alexander Graf 2013-07-25 13:38 ` Alexander Graf 2013-07-25 13:40 ` Alexander Graf 2013-07-25 13:40 ` Alexander Graf 2013-07-11 11:50 ` [PATCH 2/8] KVM: PPC: Book3S PR: Keep volatile reg values in vcpu rather than shadow_vcpu Paul Mackerras 2013-07-11 11:50 ` Paul Mackerras 2013-07-13 12:21 ` [PATCH v2 " Paul Mackerras 2013-07-13 12:21 ` Paul Mackerras 2013-07-25 13:54 ` [PATCH " Alexander Graf 2013-07-25 13:54 ` Alexander Graf 2013-08-03 2:00 ` Paul Mackerras 2013-08-03 2:00 ` Paul Mackerras 2013-07-11 11:51 ` [PATCH 3/8] KVM: PPC: Book3S PR: Rework kvmppc_mmu_book3s_64_xlate() Paul Mackerras 2013-07-11 11:51 ` Paul Mackerras 2013-07-11 11:52 ` [PATCH 4/8] KVM: PPC: Book3S PR: Allow guest to use 64k pages Paul Mackerras 2013-07-11 11:52 ` Paul Mackerras 2013-07-11 11:53 ` [PATCH 5/8] KVM: PPC: Book3S PR: Use 64k host pages where possible Paul Mackerras 2013-07-11 11:53 ` Paul Mackerras 2013-07-11 11:53 ` [PATCH 6/8] KVM: PPC: Book3S PR: Handle PP0 page-protection bit in guest HPTEs Paul Mackerras 2013-07-11 11:53 ` Paul Mackerras 2013-07-11 11:54 ` [PATCH 7/8] KVM: PPC: Book3S PR: Correct errors in H_ENTER implementation Paul Mackerras 2013-07-11 11:54 ` Paul Mackerras 2013-07-11 11:55 ` [PATCH 8/8] KVM: PPC: Book3S PR: Make HPT accesses and updates SMP-safe Paul Mackerras 2013-07-11 11:55 ` Paul Mackerras 2013-07-12 1:59 ` [PATCH v2 " Paul Mackerras 2013-07-12 1:59 ` Paul Mackerras
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