From 96e82b6bc9d47f73c0afdfb54899070d8ca83f41 Mon Sep 17 00:00:00 2001 From: Paul Mackerras Date: Tue, 25 Sep 2012 20:33:06 +0000 Subject: [PATCH] KVM: PPC: Book3S HV: Provide a way for userspace to get/set per-vCPU areas The PAPR paravirtualization interface lets guests register three different types of per-vCPU buffer areas in its memory for communication with the hypervisor. These are called virtual processor areas (VPAs). Currently the hypercalls to register and unregister VPAs are handled by KVM in the kernel, and userspace has no way to know about or save and restore these registrations across a migration. This adds "register" codes for these three areas that userspace can use with the KVM_GET/SET_ONE_REG ioctls to see what addresses have been registered, and to register or unregister them. This will be needed for guest hibernation and migration, and is also needed so that userspace can unregister them on reset (otherwise we corrupt guest memory after reboot by writing to the VPAs registered by the previous kernel). The "register" for the VPA is a 64-bit value containing the address, since the length of the VPA is fixed. The "registers" for the SLB shadow buffer and dispatch trace log (DTL) are 128 bits long, consisting of the guest physical address in the high (first) 64 bits and the length in the low 64 bits. This also fixes a bug where we were calling init_vpa unconditionally, leading to an oops when unregistering the VPA. Signed-off-by: Paul Mackerras Signed-off-by: Alexander Graf --- Documentation/virtual/kvm/api.txt | 3 ++ arch/powerpc/include/asm/kvm.h | 6 +++ arch/powerpc/include/asm/kvm_ppc.h | 4 ++ arch/powerpc/kvm/book3s_hv.c | 64 +++++++++++++++++++++++++++++- 4 files changed, 76 insertions(+), 1 deletion(-) diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index 975bb4c7f7e1..2a4d868a3df1 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -1770,6 +1770,9 @@ registers, find a list below: PPC | KVM_REG_PPC_VSR31 | 128 PPC | KVM_REG_PPC_FPSCR | 64 PPC | KVM_REG_PPC_VSCR | 32 + PPC | KVM_REG_PPC_VPA_ADDR | 64 + PPC | KVM_REG_PPC_VPA_SLB | 128 + PPC | KVM_REG_PPC_VPA_DTL | 128 4.69 KVM_GET_ONE_REG diff --git a/arch/powerpc/include/asm/kvm.h b/arch/powerpc/include/asm/kvm.h index 1466975129c7..b89ae4db45ce 100644 --- a/arch/powerpc/include/asm/kvm.h +++ b/arch/powerpc/include/asm/kvm.h @@ -380,4 +380,10 @@ struct kvm_book3e_206_tlb_params { #define KVM_REG_PPC_FPSCR (KVM_REG_PPC | KVM_REG_SIZE_U64 | 0x80) #define KVM_REG_PPC_VSCR (KVM_REG_PPC | KVM_REG_SIZE_U32 | 0x81) +/* Virtual processor areas */ +/* For SLB & DTL, address in high (first) half, length in low half */ +#define KVM_REG_PPC_VPA_ADDR (KVM_REG_PPC | KVM_REG_SIZE_U64 | 0x82) +#define KVM_REG_PPC_VPA_SLB (KVM_REG_PPC | KVM_REG_SIZE_U128 | 0x83) +#define KVM_REG_PPC_VPA_DTL (KVM_REG_PPC | KVM_REG_SIZE_U128 | 0x84) + #endif /* __LINUX_KVM_POWERPC_H */ diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h index 51604a16c8a5..609cca3e9426 100644 --- a/arch/powerpc/include/asm/kvm_ppc.h +++ b/arch/powerpc/include/asm/kvm_ppc.h @@ -202,6 +202,10 @@ union kvmppc_one_reg { u64 dval; vector128 vval; u64 vsxval[2]; + struct { + u64 addr; + u64 length; + } vpaval; }; #define one_reg_size(id) \ diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index 94ec0e30969d..9a15da76e56b 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -143,6 +143,22 @@ static void init_vpa(struct kvm_vcpu *vcpu, struct lppaca *vpa) vpa->yield_count = 1; } +static int set_vpa(struct kvm_vcpu *vcpu, struct kvmppc_vpa *v, + unsigned long addr, unsigned long len) +{ + /* check address is cacheline aligned */ + if (addr & (L1_CACHE_BYTES - 1)) + return -EINVAL; + spin_lock(&vcpu->arch.vpa_update_lock); + if (v->next_gpa != addr || v->len != len) { + v->next_gpa = addr; + v->len = addr ? len : 0; + v->update_pending = 1; + } + spin_unlock(&vcpu->arch.vpa_update_lock); + return 0; +} + /* Length for a per-processor buffer is passed in at offset 4 in the buffer */ struct reg_vpa { u32 dummy; @@ -321,7 +337,8 @@ static void kvmppc_update_vpas(struct kvm_vcpu *vcpu) spin_lock(&vcpu->arch.vpa_update_lock); if (vcpu->arch.vpa.update_pending) { kvmppc_update_vpa(vcpu, &vcpu->arch.vpa); - init_vpa(vcpu, vcpu->arch.vpa.pinned_addr); + if (vcpu->arch.vpa.pinned_addr) + init_vpa(vcpu, vcpu->arch.vpa.pinned_addr); } if (vcpu->arch.dtl.update_pending) { kvmppc_update_vpa(vcpu, &vcpu->arch.dtl); @@ -600,6 +617,23 @@ int kvmppc_get_one_reg(struct kvm_vcpu *vcpu, u64 id, union kvmppc_one_reg *val) } break; #endif /* CONFIG_VSX */ + case KVM_REG_PPC_VPA_ADDR: + spin_lock(&vcpu->arch.vpa_update_lock); + *val = get_reg_val(id, vcpu->arch.vpa.next_gpa); + spin_unlock(&vcpu->arch.vpa_update_lock); + break; + case KVM_REG_PPC_VPA_SLB: + spin_lock(&vcpu->arch.vpa_update_lock); + val->vpaval.addr = vcpu->arch.slb_shadow.next_gpa; + val->vpaval.length = vcpu->arch.slb_shadow.len; + spin_unlock(&vcpu->arch.vpa_update_lock); + break; + case KVM_REG_PPC_VPA_DTL: + spin_lock(&vcpu->arch.vpa_update_lock); + val->vpaval.addr = vcpu->arch.dtl.next_gpa; + val->vpaval.length = vcpu->arch.dtl.len; + spin_unlock(&vcpu->arch.vpa_update_lock); + break; default: r = -EINVAL; break; @@ -612,6 +646,7 @@ int kvmppc_set_one_reg(struct kvm_vcpu *vcpu, u64 id, union kvmppc_one_reg *val) { int r = 0; long int i; + unsigned long addr, len; switch (id) { case KVM_REG_PPC_HIOR: @@ -666,6 +701,33 @@ int kvmppc_set_one_reg(struct kvm_vcpu *vcpu, u64 id, union kvmppc_one_reg *val) } break; #endif /* CONFIG_VSX */ + case KVM_REG_PPC_VPA_ADDR: + addr = set_reg_val(id, *val); + r = -EINVAL; + if (!addr && (vcpu->arch.slb_shadow.next_gpa || + vcpu->arch.dtl.next_gpa)) + break; + r = set_vpa(vcpu, &vcpu->arch.vpa, addr, sizeof(struct lppaca)); + break; + case KVM_REG_PPC_VPA_SLB: + addr = val->vpaval.addr; + len = val->vpaval.length; + r = -EINVAL; + if (addr && !vcpu->arch.vpa.next_gpa) + break; + r = set_vpa(vcpu, &vcpu->arch.slb_shadow, addr, len); + break; + case KVM_REG_PPC_VPA_DTL: + addr = val->vpaval.addr; + len = val->vpaval.length; + r = -EINVAL; + if (len < sizeof(struct dtl_entry)) + break; + if (addr && !vcpu->arch.vpa.next_gpa) + break; + len -= len % sizeof(struct dtl_entry); + r = set_vpa(vcpu, &vcpu->arch.dtl, addr, len); + break; default: r = -EINVAL; break; -- 2.39.5