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Merge branch kvm-arm64/psci-1.1 into kvmarm-master/next
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* kvm-arm64/psci-1.1:
  : .
  : Limited PSCI-1.1 support from Will Deacon:
  :
  : This small series exposes the PSCI SYSTEM_RESET2 call to guests, which
  : allows the propagation of a "reset_type" and a "cookie" back to the VMM.
  : Although Linux guests only ever pass 0 for the type ("SYSTEM_WARM_RESET"),
  : the vendor-defined range can be used by a bootloader to provide additional
  : information about the reset, such as an error code.
  : .
  KVM: arm64: Remove unneeded semicolons
  KVM: arm64: Indicate SYSTEM_RESET2 in kvm_run::system_event flags field
  KVM: arm64: Expose PSCI SYSTEM_RESET2 call to the guest
  KVM: arm64: Bump guest PSCI version to 1.1

Signed-off-by: Marc Zyngier <maz@kernel.org>
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Marc Zyngier committed Feb 25, 2022
2 parents 00e6dae + ae82047 commit 1a48ce9
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Showing 5 changed files with 67 additions and 12 deletions.
5 changes: 5 additions & 0 deletions Documentation/virt/kvm/api.rst
Original file line number Diff line number Diff line change
Expand Up @@ -5939,6 +5939,11 @@ Valid values for 'type' are:
to ignore the request, or to gather VM memory core dump and/or
reset/shutdown of the VM.

Valid flags are:

- KVM_SYSTEM_EVENT_RESET_FLAG_PSCI_RESET2 (arm64 only) -- the guest issued
a SYSTEM_RESET2 call according to v1.1 of the PSCI specification.

::

/* KVM_EXIT_IOAPIC_EOI */
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7 changes: 7 additions & 0 deletions arch/arm64/include/uapi/asm/kvm.h
Original file line number Diff line number Diff line change
Expand Up @@ -414,6 +414,13 @@ struct kvm_arm_copy_mte_tags {
#define KVM_PSCI_RET_INVAL PSCI_RET_INVALID_PARAMS
#define KVM_PSCI_RET_DENIED PSCI_RET_DENIED

/* arm64-specific kvm_run::system_event flags */
/*
* Reset caused by a PSCI v1.1 SYSTEM_RESET2 call.
* Valid only when the system event has a type of KVM_SYSTEM_EVENT_RESET.
*/
#define KVM_SYSTEM_EVENT_RESET_FLAG_PSCI_RESET2 (1ULL << 0)

/* run->fail_entry.hardware_entry_failure_reason codes. */
#define KVM_EXIT_FAIL_ENTRY_CPU_UNSUPPORTED (1ULL << 0)

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60 changes: 49 additions & 11 deletions arch/arm64/kvm/psci.c
Original file line number Diff line number Diff line change
Expand Up @@ -162,7 +162,7 @@ static unsigned long kvm_psci_vcpu_affinity_info(struct kvm_vcpu *vcpu)
return PSCI_0_2_AFFINITY_LEVEL_OFF;
}

static void kvm_prepare_system_event(struct kvm_vcpu *vcpu, u32 type)
static void kvm_prepare_system_event(struct kvm_vcpu *vcpu, u32 type, u64 flags)
{
unsigned long i;
struct kvm_vcpu *tmp;
Expand All @@ -182,17 +182,24 @@ static void kvm_prepare_system_event(struct kvm_vcpu *vcpu, u32 type)

memset(&vcpu->run->system_event, 0, sizeof(vcpu->run->system_event));
vcpu->run->system_event.type = type;
vcpu->run->system_event.flags = flags;
vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
}

static void kvm_psci_system_off(struct kvm_vcpu *vcpu)
{
kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_SHUTDOWN);
kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_SHUTDOWN, 0);
}

static void kvm_psci_system_reset(struct kvm_vcpu *vcpu)
{
kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_RESET);
kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_RESET, 0);
}

static void kvm_psci_system_reset2(struct kvm_vcpu *vcpu)
{
kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_RESET,
KVM_SYSTEM_EVENT_RESET_FLAG_PSCI_RESET2);
}

static void kvm_psci_narrow_to_32bit(struct kvm_vcpu *vcpu)
Expand Down Expand Up @@ -305,24 +312,27 @@ static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu)
return ret;
}

static int kvm_psci_1_0_call(struct kvm_vcpu *vcpu)
static int kvm_psci_1_x_call(struct kvm_vcpu *vcpu, u32 minor)
{
u32 psci_fn = smccc_get_function(vcpu);
u32 feature;
u32 arg;
unsigned long val;
int ret = 1;

if (minor > 1)
return -EINVAL;

switch(psci_fn) {
case PSCI_0_2_FN_PSCI_VERSION:
val = KVM_ARM_PSCI_1_0;
val = minor == 0 ? KVM_ARM_PSCI_1_0 : KVM_ARM_PSCI_1_1;
break;
case PSCI_1_0_FN_PSCI_FEATURES:
feature = smccc_get_arg1(vcpu);
val = kvm_psci_check_allowed_function(vcpu, feature);
arg = smccc_get_arg1(vcpu);
val = kvm_psci_check_allowed_function(vcpu, arg);
if (val)
break;

switch(feature) {
switch(arg) {
case PSCI_0_2_FN_PSCI_VERSION:
case PSCI_0_2_FN_CPU_SUSPEND:
case PSCI_0_2_FN64_CPU_SUSPEND:
Expand All @@ -338,11 +348,36 @@ static int kvm_psci_1_0_call(struct kvm_vcpu *vcpu)
case ARM_SMCCC_VERSION_FUNC_ID:
val = 0;
break;
case PSCI_1_1_FN_SYSTEM_RESET2:
case PSCI_1_1_FN64_SYSTEM_RESET2:
if (minor >= 1) {
val = 0;
break;
}
fallthrough;
default:
val = PSCI_RET_NOT_SUPPORTED;
break;
}
break;
case PSCI_1_1_FN_SYSTEM_RESET2:
kvm_psci_narrow_to_32bit(vcpu);
fallthrough;
case PSCI_1_1_FN64_SYSTEM_RESET2:
if (minor >= 1) {
arg = smccc_get_arg1(vcpu);

if (arg > PSCI_1_1_RESET_TYPE_SYSTEM_WARM_RESET &&
arg < PSCI_1_1_RESET_TYPE_VENDOR_START) {
val = PSCI_RET_INVALID_PARAMS;
} else {
kvm_psci_system_reset2(vcpu);
val = PSCI_RET_INTERNAL_FAILURE;
ret = 0;
}
break;
}
fallthrough;
default:
return kvm_psci_0_2_call(vcpu);
}
Expand Down Expand Up @@ -393,15 +428,17 @@ static int kvm_psci_0_1_call(struct kvm_vcpu *vcpu)
int kvm_psci_call(struct kvm_vcpu *vcpu)
{
switch (kvm_psci_version(vcpu)) {
case KVM_ARM_PSCI_1_1:
return kvm_psci_1_x_call(vcpu, 1);
case KVM_ARM_PSCI_1_0:
return kvm_psci_1_0_call(vcpu);
return kvm_psci_1_x_call(vcpu, 0);
case KVM_ARM_PSCI_0_2:
return kvm_psci_0_2_call(vcpu);
case KVM_ARM_PSCI_0_1:
return kvm_psci_0_1_call(vcpu);
default:
return -EINVAL;
};
}
}

int kvm_arm_get_fw_num_regs(struct kvm_vcpu *vcpu)
Expand Down Expand Up @@ -511,6 +548,7 @@ int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
return 0;
case KVM_ARM_PSCI_0_2:
case KVM_ARM_PSCI_1_0:
case KVM_ARM_PSCI_1_1:
if (!wants_02)
return -EINVAL;
vcpu->kvm->arch.psci_version = val;
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3 changes: 2 additions & 1 deletion include/kvm/arm_psci.h
Original file line number Diff line number Diff line change
Expand Up @@ -13,8 +13,9 @@
#define KVM_ARM_PSCI_0_1 PSCI_VERSION(0, 1)
#define KVM_ARM_PSCI_0_2 PSCI_VERSION(0, 2)
#define KVM_ARM_PSCI_1_0 PSCI_VERSION(1, 0)
#define KVM_ARM_PSCI_1_1 PSCI_VERSION(1, 1)

#define KVM_ARM_PSCI_LATEST KVM_ARM_PSCI_1_0
#define KVM_ARM_PSCI_LATEST KVM_ARM_PSCI_1_1

static inline int kvm_psci_version(struct kvm_vcpu *vcpu)
{
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4 changes: 4 additions & 0 deletions include/uapi/linux/psci.h
Original file line number Diff line number Diff line change
Expand Up @@ -82,6 +82,10 @@
#define PSCI_0_2_TOS_UP_NO_MIGRATE 1
#define PSCI_0_2_TOS_MP 2

/* PSCI v1.1 reset type encoding for SYSTEM_RESET2 */
#define PSCI_1_1_RESET_TYPE_SYSTEM_WARM_RESET 0
#define PSCI_1_1_RESET_TYPE_VENDOR_START 0x80000000U

/* PSCI version decoding (independent of PSCI version) */
#define PSCI_VERSION_MAJOR_SHIFT 16
#define PSCI_VERSION_MINOR_MASK \
Expand Down

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