From 021ec9c69f8b7b20f46296cc76cc4cb341b25191 Mon Sep 17 00:00:00 2001 From: Alexander Graf Date: Fri, 8 Jan 2010 02:58:06 +0100 Subject: KVM: PPC: Call SLB patching code in interrupt safe manner Currently we're racy when doing the transition from IR=1 to IR=0, from the module memory entry code to the real mode SLB switching code. To work around that I took a look at the RTAS entry code which is faced with a similar problem and did the same thing: A small helper in linear mapped memory that does mtmsr with IR=0 and then RFIs info the actual handler. Thanks to that trick we can safely take page faults in the entry code and only need to be really wary of what to do as of the SLB switching part. Signed-off-by: Alexander Graf Signed-off-by: Avi Kivity --- arch/powerpc/kvm/book3s.c | 1 + arch/powerpc/kvm/book3s_64_exports.c | 1 + arch/powerpc/kvm/book3s_64_interrupts.S | 25 +++++++------------------ arch/powerpc/kvm/book3s_64_rmhandlers.S | 18 ++++++++++++++++++ arch/powerpc/kvm/book3s_64_slb.S | 4 ++++ 5 files changed, 31 insertions(+), 18 deletions(-) (limited to 'arch/powerpc/kvm') diff --git a/arch/powerpc/kvm/book3s.c b/arch/powerpc/kvm/book3s.c index 3e06eae3f2c..13173922b67 100644 --- a/arch/powerpc/kvm/book3s.c +++ b/arch/powerpc/kvm/book3s.c @@ -919,6 +919,7 @@ struct kvm_vcpu *kvmppc_core_vcpu_create(struct kvm *kvm, unsigned int id) vcpu->arch.trampoline_lowmem = kvmppc_trampoline_lowmem; vcpu->arch.trampoline_enter = kvmppc_trampoline_enter; vcpu->arch.highmem_handler = (ulong)kvmppc_handler_highmem; + vcpu->arch.rmcall = *(ulong*)kvmppc_rmcall; vcpu->arch.shadow_msr = MSR_USER64; diff --git a/arch/powerpc/kvm/book3s_64_exports.c b/arch/powerpc/kvm/book3s_64_exports.c index 5b2db38ed86..99b07125c52 100644 --- a/arch/powerpc/kvm/book3s_64_exports.c +++ b/arch/powerpc/kvm/book3s_64_exports.c @@ -22,3 +22,4 @@ EXPORT_SYMBOL_GPL(kvmppc_trampoline_enter); EXPORT_SYMBOL_GPL(kvmppc_trampoline_lowmem); +EXPORT_SYMBOL_GPL(kvmppc_rmcall); diff --git a/arch/powerpc/kvm/book3s_64_interrupts.S b/arch/powerpc/kvm/book3s_64_interrupts.S index 3c0ba551307..33aef5345f6 100644 --- a/arch/powerpc/kvm/book3s_64_interrupts.S +++ b/arch/powerpc/kvm/book3s_64_interrupts.S @@ -95,17 +95,14 @@ kvm_start_entry: ld r3, VCPU_HIGHMEM_HANDLER(r4) std r3, PACA_KVM_VMHANDLER(r13) - ld r3, VCPU_TRAMPOLINE_ENTER(r4) - std r3, PACA_KVM_RMHANDLER(r13) - kvm_start_lightweight: ld r9, VCPU_PC(r4) /* r9 = vcpu->arch.pc */ ld r10, VCPU_SHADOW_MSR(r4) /* r10 = vcpu->arch.shadow_msr */ /* Load some guest state in the respective registers */ - ld r3, VCPU_CTR(r4) /* r3 = vcpu->arch.ctr */ - mtctr r3 /* CTR = r3 */ + ld r5, VCPU_CTR(r4) /* r5 = vcpu->arch.ctr */ + /* will be swapped in by rmcall */ ld r3, VCPU_LR(r4) /* r3 = vcpu->arch.lr */ mtlr r3 /* LR = r3 */ @@ -131,22 +128,14 @@ kvm_start_lightweight: no_dcbz32_on: - /* This sets the Magic value for the trampoline */ - - /* XXX this needs to move into a safe function, so we can - be sure we don't get any interrupts */ - - li r11, 1 - stb r11, PACA_KVM_IN_GUEST(r13) - - ld r3, PACA_KVM_RMHANDLER(r13) - mtsrr0 r3 + ld r6, VCPU_RMCALL(r4) + mtctr r6 - LOAD_REG_IMMEDIATE(r3, MSR_KERNEL & ~(MSR_IR | MSR_DR)) - mtsrr1 r3 + ld r3, VCPU_TRAMPOLINE_ENTER(r4) + LOAD_REG_IMMEDIATE(r4, MSR_KERNEL & ~(MSR_IR | MSR_DR)) /* Jump to SLB patching handlder and into our guest */ - RFI + bctr /* * This is the handler in module memory. It gets jumped at from the diff --git a/arch/powerpc/kvm/book3s_64_rmhandlers.S b/arch/powerpc/kvm/book3s_64_rmhandlers.S index 9ad1c2645d6..e7091c9459a 100644 --- a/arch/powerpc/kvm/book3s_64_rmhandlers.S +++ b/arch/powerpc/kvm/book3s_64_rmhandlers.S @@ -140,6 +140,24 @@ kvmppc_handler_lowmem_trampoline: blr kvmppc_handler_lowmem_trampoline_end: +/* + * Call a function in real mode + * + * Input Registers: + * + * R3 = function + * R4 = MSR + * R5 = CTR + * + */ +_GLOBAL(kvmppc_rmcall) + mtmsr r4 /* Disable relocation, so mtsrr + doesn't get interrupted */ + mtctr r5 + mtsrr0 r3 + mtsrr1 r4 + RFI + .global kvmppc_trampoline_lowmem kvmppc_trampoline_lowmem: .long kvmppc_handler_lowmem_trampoline - _stext diff --git a/arch/powerpc/kvm/book3s_64_slb.S b/arch/powerpc/kvm/book3s_64_slb.S index d07b88617b2..35b76272218 100644 --- a/arch/powerpc/kvm/book3s_64_slb.S +++ b/arch/powerpc/kvm/book3s_64_slb.S @@ -63,6 +63,10 @@ kvmppc_handler_trampoline_enter: mtsrr0 r9 mtsrr1 r10 + /* Activate guest mode, so faults get handled by KVM */ + li r11, KVM_GUEST_MODE_GUEST + stb r11, PACA_KVM_IN_GUEST(r13) + /* Remove LPAR shadow entries */ #if SLB_NUM_BOLTED == 3 -- cgit v1.2.3-18-g5258