[PATCH 4.14 086/195] [Variant 2/Spectre-v2] arm/arm64: KVM: Turn kvm_psci_version into a static inline

From: Greg Kroah-Hartman
Date: Thu Feb 15 2018 - 10:35:32 EST


4.14-stable review patch. If anyone has any objections, please let me know.

------------------

From: Marc Zyngier <marc.zyngier@xxxxxxx>


Commit a4097b351118 upstream.

We're about to need kvm_psci_version in HYP too. So let's turn it
into a static inline, and pass the kvm structure as a second
parameter (so that HYP can do a kern_hyp_va on it).

Tested-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Reviewed-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm64/kvm/hyp/switch.c | 18 +++++++++++-------
include/kvm/arm_psci.h | 21 ++++++++++++++++++++-
virt/kvm/arm/psci.c | 12 ++----------
3 files changed, 33 insertions(+), 18 deletions(-)

--- a/arch/arm64/kvm/hyp/switch.c
+++ b/arch/arm64/kvm/hyp/switch.c
@@ -19,6 +19,8 @@
#include <linux/jump_label.h>
#include <uapi/linux/psci.h>

+#include <kvm/arm_psci.h>
+
#include <asm/kvm_asm.h>
#include <asm/kvm_emulate.h>
#include <asm/kvm_hyp.h>
@@ -325,14 +327,16 @@ again:

if (exit_code == ARM_EXCEPTION_TRAP &&
(kvm_vcpu_trap_get_class(vcpu) == ESR_ELx_EC_HVC64 ||
- kvm_vcpu_trap_get_class(vcpu) == ESR_ELx_EC_HVC32) &&
- vcpu_get_reg(vcpu, 0) == PSCI_0_2_FN_PSCI_VERSION) {
- u64 val = PSCI_RET_NOT_SUPPORTED;
- if (test_bit(KVM_ARM_VCPU_PSCI_0_2, vcpu->arch.features))
- val = 2;
+ kvm_vcpu_trap_get_class(vcpu) == ESR_ELx_EC_HVC32)) {
+ u32 val = vcpu_get_reg(vcpu, 0);

- vcpu_set_reg(vcpu, 0, val);
- goto again;
+ if (val == PSCI_0_2_FN_PSCI_VERSION) {
+ val = kvm_psci_version(vcpu, kern_hyp_va(vcpu->kvm));
+ if (unlikely(val == KVM_ARM_PSCI_0_1))
+ val = PSCI_RET_NOT_SUPPORTED;
+ vcpu_set_reg(vcpu, 0, val);
+ goto again;
+ }
}

if (static_branch_unlikely(&vgic_v2_cpuif_trap) &&
--- a/include/kvm/arm_psci.h
+++ b/include/kvm/arm_psci.h
@@ -18,6 +18,7 @@
#ifndef __KVM_ARM_PSCI_H__
#define __KVM_ARM_PSCI_H__

+#include <linux/kvm_host.h>
#include <uapi/linux/psci.h>

#define KVM_ARM_PSCI_0_1 PSCI_VERSION(0, 1)
@@ -26,7 +27,25 @@

#define KVM_ARM_PSCI_LATEST KVM_ARM_PSCI_1_0

-int kvm_psci_version(struct kvm_vcpu *vcpu);
+/*
+ * We need the KVM pointer independently from the vcpu as we can call
+ * this from HYP, and need to apply kern_hyp_va on it...
+ */
+static inline int kvm_psci_version(struct kvm_vcpu *vcpu, struct kvm *kvm)
+{
+ /*
+ * Our PSCI implementation stays the same across versions from
+ * v0.2 onward, only adding the few mandatory functions (such
+ * as FEATURES with 1.0) that are required by newer
+ * revisions. It is thus safe to return the latest.
+ */
+ if (test_bit(KVM_ARM_VCPU_PSCI_0_2, vcpu->arch.features))
+ return KVM_ARM_PSCI_LATEST;
+
+ return KVM_ARM_PSCI_0_1;
+}
+
+
int kvm_hvc_call_handler(struct kvm_vcpu *vcpu);

#endif /* __KVM_ARM_PSCI_H__ */
--- a/virt/kvm/arm/psci.c
+++ b/virt/kvm/arm/psci.c
@@ -123,7 +123,7 @@ static unsigned long kvm_psci_vcpu_on(st
if (!vcpu)
return PSCI_RET_INVALID_PARAMS;
if (!vcpu->arch.power_off) {
- if (kvm_psci_version(source_vcpu) != KVM_ARM_PSCI_0_1)
+ if (kvm_psci_version(source_vcpu, kvm) != KVM_ARM_PSCI_0_1)
return PSCI_RET_ALREADY_ON;
else
return PSCI_RET_INVALID_PARAMS;
@@ -232,14 +232,6 @@ static void kvm_psci_system_reset(struct
kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_RESET);
}

-int kvm_psci_version(struct kvm_vcpu *vcpu)
-{
- if (test_bit(KVM_ARM_VCPU_PSCI_0_2, vcpu->arch.features))
- return KVM_ARM_PSCI_LATEST;
-
- return KVM_ARM_PSCI_0_1;
-}
-
static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu)
{
struct kvm *kvm = vcpu->kvm;
@@ -397,7 +389,7 @@ static int kvm_psci_0_1_call(struct kvm_
*/
static int kvm_psci_call(struct kvm_vcpu *vcpu)
{
- switch (kvm_psci_version(vcpu)) {
+ switch (kvm_psci_version(vcpu, vcpu->kvm)) {
case KVM_ARM_PSCI_1_0:
return kvm_psci_1_0_call(vcpu);
case KVM_ARM_PSCI_0_2: