arm/arm64: KVM: Add PSCI version selection API
Although we've implemented PSCI 0.1, 0.2 and 1.0, we expose either 0.1
or 1.0 to a guest, defaulting to the latest version of the PSCI
implementation that is compatible with the requested version. This is
no different from doing a firmware upgrade on KVM.
But in order to give a chance to hypothetical badly implemented guests
that would have a fit by discovering something other than PSCI 0.2,
let's provide a new API that allows userspace to pick one particular
version of the API.
This is implemented as a new class of "firmware" registers, where
we expose the PSCI version. This allows the PSCI version to be
save/restored as part of a guest migration, and also set to
any supported version if the guest requires it.
Cc: stable@vger.kernel.org #4.16
Reviewed-by: Christoffer Dall <cdall@kernel.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index c6a7495..c7c28c8 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -77,6 +77,9 @@ struct kvm_arch {
/* Interrupt controller */
struct vgic_dist vgic;
int max_vcpus;
+
+ /* Mandated version of PSCI */
+ u32 psci_version;
};
#define KVM_NR_MEM_OBJS 40
diff --git a/arch/arm/include/uapi/asm/kvm.h b/arch/arm/include/uapi/asm/kvm.h
index 2ba95d6..caae484 100644
--- a/arch/arm/include/uapi/asm/kvm.h
+++ b/arch/arm/include/uapi/asm/kvm.h
@@ -195,6 +195,12 @@ struct kvm_arch_memory_slot {
#define KVM_REG_ARM_VFP_FPINST 0x1009
#define KVM_REG_ARM_VFP_FPINST2 0x100A
+/* KVM-as-firmware specific pseudo-registers */
+#define KVM_REG_ARM_FW (0x0014 << KVM_REG_ARM_COPROC_SHIFT)
+#define KVM_REG_ARM_FW_REG(r) (KVM_REG_ARM | KVM_REG_SIZE_U64 | \
+ KVM_REG_ARM_FW | ((r) & 0xffff))
+#define KVM_REG_ARM_PSCI_VERSION KVM_REG_ARM_FW_REG(0)
+
/* Device Control API: ARM VGIC */
#define KVM_DEV_ARM_VGIC_GRP_ADDR 0
#define KVM_DEV_ARM_VGIC_GRP_DIST_REGS 1
diff --git a/arch/arm/kvm/guest.c b/arch/arm/kvm/guest.c
index 1e0784e..a18f33e 100644
--- a/arch/arm/kvm/guest.c
+++ b/arch/arm/kvm/guest.c
@@ -22,6 +22,7 @@
#include <linux/module.h>
#include <linux/vmalloc.h>
#include <linux/fs.h>
+#include <kvm/arm_psci.h>
#include <asm/cputype.h>
#include <linux/uaccess.h>
#include <asm/kvm.h>
@@ -176,6 +177,7 @@ static unsigned long num_core_regs(void)
unsigned long kvm_arm_num_regs(struct kvm_vcpu *vcpu)
{
return num_core_regs() + kvm_arm_num_coproc_regs(vcpu)
+ + kvm_arm_get_fw_num_regs(vcpu)
+ NUM_TIMER_REGS;
}
@@ -196,6 +198,11 @@ int kvm_arm_copy_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
uindices++;
}
+ ret = kvm_arm_copy_fw_reg_indices(vcpu, uindices);
+ if (ret)
+ return ret;
+ uindices += kvm_arm_get_fw_num_regs(vcpu);
+
ret = copy_timer_indices(vcpu, uindices);
if (ret)
return ret;
@@ -214,6 +221,9 @@ int kvm_arm_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_CORE)
return get_core_reg(vcpu, reg);
+ if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_FW)
+ return kvm_arm_get_fw_reg(vcpu, reg);
+
if (is_timer_reg(reg->id))
return get_timer_reg(vcpu, reg);
@@ -230,6 +240,9 @@ int kvm_arm_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_CORE)
return set_core_reg(vcpu, reg);
+ if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_FW)
+ return kvm_arm_set_fw_reg(vcpu, reg);
+
if (is_timer_reg(reg->id))
return set_timer_reg(vcpu, reg);
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index ab46bc7..469de8a 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -75,6 +75,9 @@ struct kvm_arch {
/* Interrupt controller */
struct vgic_dist vgic;
+
+ /* Mandated version of PSCI */
+ u32 psci_version;
};
#define KVM_NR_MEM_OBJS 40
diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
index 9abbf30..04b3256 100644
--- a/arch/arm64/include/uapi/asm/kvm.h
+++ b/arch/arm64/include/uapi/asm/kvm.h
@@ -206,6 +206,12 @@ struct kvm_arch_memory_slot {
#define KVM_REG_ARM_TIMER_CNT ARM64_SYS_REG(3, 3, 14, 3, 2)
#define KVM_REG_ARM_TIMER_CVAL ARM64_SYS_REG(3, 3, 14, 0, 2)
+/* KVM-as-firmware specific pseudo-registers */
+#define KVM_REG_ARM_FW (0x0014 << KVM_REG_ARM_COPROC_SHIFT)
+#define KVM_REG_ARM_FW_REG(r) (KVM_REG_ARM64 | KVM_REG_SIZE_U64 | \
+ KVM_REG_ARM_FW | ((r) & 0xffff))
+#define KVM_REG_ARM_PSCI_VERSION KVM_REG_ARM_FW_REG(0)
+
/* Device Control API: ARM VGIC */
#define KVM_DEV_ARM_VGIC_GRP_ADDR 0
#define KVM_DEV_ARM_VGIC_GRP_DIST_REGS 1
diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
index 959e50d..56a0260 100644
--- a/arch/arm64/kvm/guest.c
+++ b/arch/arm64/kvm/guest.c
@@ -25,6 +25,7 @@
#include <linux/module.h>
#include <linux/vmalloc.h>
#include <linux/fs.h>
+#include <kvm/arm_psci.h>
#include <asm/cputype.h>
#include <linux/uaccess.h>
#include <asm/kvm.h>
@@ -205,7 +206,7 @@ static int get_timer_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
unsigned long kvm_arm_num_regs(struct kvm_vcpu *vcpu)
{
return num_core_regs() + kvm_arm_num_sys_reg_descs(vcpu)
- + NUM_TIMER_REGS;
+ + kvm_arm_get_fw_num_regs(vcpu) + NUM_TIMER_REGS;
}
/**
@@ -225,6 +226,11 @@ int kvm_arm_copy_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
uindices++;
}
+ ret = kvm_arm_copy_fw_reg_indices(vcpu, uindices);
+ if (ret)
+ return ret;
+ uindices += kvm_arm_get_fw_num_regs(vcpu);
+
ret = copy_timer_indices(vcpu, uindices);
if (ret)
return ret;
@@ -243,6 +249,9 @@ int kvm_arm_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_CORE)
return get_core_reg(vcpu, reg);
+ if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_FW)
+ return kvm_arm_get_fw_reg(vcpu, reg);
+
if (is_timer_reg(reg->id))
return get_timer_reg(vcpu, reg);
@@ -259,6 +268,9 @@ int kvm_arm_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_CORE)
return set_core_reg(vcpu, reg);
+ if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_FW)
+ return kvm_arm_set_fw_reg(vcpu, reg);
+
if (is_timer_reg(reg->id))
return set_timer_reg(vcpu, reg);