From f2e91042a807cbf9b0b0d9776bf37d1ef0bd7ebe Mon Sep 17 00:00:00 2001 From: Alexander Graf Date: Thu, 22 May 2014 17:40:15 +0200 Subject: [PATCH] KVM: PPC: Add CAP to indicate hcall fixes We worked around some nasty KVM magic page hcall breakages: 1) NX bit not honored, so ignore NX when we detect it 2) LE guests swizzle hypercall instruction Without these fixes in place, there's no way it would make sense to expose kvm hypercalls to a guest. Chances are immensely high it would trip over and break. So add a new CAP that gives user space a hint that we have workarounds for the bugs above in place. It can use those as hint to disable PV hypercalls when the guest CPU is anything POWER7 or higher and the host does not have fixes in place. Signed-off-by: Alexander Graf --- arch/powerpc/kvm/powerpc.c | 1 + include/uapi/linux/kvm.h | 1 + 2 files changed, 2 insertions(+) diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c index 154f352c39ae..bab20f410443 100644 --- a/arch/powerpc/kvm/powerpc.c +++ b/arch/powerpc/kvm/powerpc.c @@ -416,6 +416,7 @@ int kvm_dev_ioctl_check_extension(long ext) case KVM_CAP_SPAPR_TCE: case KVM_CAP_PPC_ALLOC_HTAB: case KVM_CAP_PPC_RTAS: + case KVM_CAP_PPC_FIXUP_HCALL: #ifdef CONFIG_KVM_XICS case KVM_CAP_IRQ_XICS: #endif diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 2b83cf35437a..16c923de85e7 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -748,6 +748,7 @@ struct kvm_ppc_smmu_info { #define KVM_CAP_S390_IRQCHIP 99 #define KVM_CAP_IOEVENTFD_NO_LENGTH 100 #define KVM_CAP_VM_ATTRIBUTES 101 +#define KVM_CAP_PPC_FIXUP_HCALL 102 #ifdef KVM_CAP_IRQ_ROUTING -- GitLab