Re: [PATCH 00/59] KVM: arm64: ARMv8.3 Nested Virtualization support

Alexandru Elisei
2019-08-02T10:12:02Z

Hi,

On 6/21/19 10:37 AM, Marc Zyngier wrote:
> I've taken over the maintenance of this series originally written by
> Jintack and Christoffer. Since then, the series has been substantially
> reworked, new features (and most probably bugs) have been added, and
> the whole thing rebased multiple times. If anything breaks, please
> blame me, and nobody else.
>
> As you can tell, this is quite big. It is also remarkably incomplete
> (we're missing many critical bits for fully emulate EL2), but the idea
> is to start merging things early in order to reduce the maintenance
> headache. What we want to achieve is that with NV disabled, there is
> no performance overhead and no regression. The only thing I intend to
> merge ASAP is the first patch in the series, because it should have
> zero effect and is a reasonable cleanup.
>
> The series is roughly divided in 4 parts: exception handling, memory
> virtualization, interrupts and timers. There are of course some
> dependencies, but you'll hopefully get the gist of it.
>
> For the most courageous of you, I've put out a branch[1] containing this
> and a bit more. Of course, you'll need some userspace. Andre maintains
> a hacked version of kvmtool[1] that takes a --nested option, allowing
> the guest to be started at EL2. You can run the whole stack in the
> Foundation model. Don't be in a hurry ;-).
>
> [1] git://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git kvm-arm64/nv-wip-5.2-rc5
> [2] git://linux-arm.org/kvmtool.git nv/nv-wip-5.2-rc5
>
> Andre Przywara (4):
> KVM: arm64: nv: Handle virtual EL2 registers in
> vcpu_read/write_sys_reg()
> KVM: arm64: nv: Save/Restore vEL2 sysregs
> KVM: arm64: nv: Handle traps for timer _EL02 and _EL2 sysregs
> accessors
> KVM: arm64: nv: vgic: Allow userland to set VGIC maintenance IRQ
>
> Christoffer Dall (16):
> KVM: arm64: nv: Introduce nested virtualization VCPU feature
> KVM: arm64: nv: Reset VCPU to EL2 registers if VCPU nested virt is set
> KVM: arm64: nv: Allow userspace to set PSR_MODE_EL2x
> KVM: arm64: nv: Add nested virt VCPU primitives for vEL2 VCPU state
> KVM: arm64: nv: Handle trapped ERET from virtual EL2
> KVM: arm64: nv: Emulate PSTATE.M for a guest hypervisor
> KVM: arm64: nv: Trap EL1 VM register accesses in virtual EL2
> KVM: arm64: nv: Only toggle cache for virtual EL2 when SCTLR_EL2
> changes
> KVM: arm/arm64: nv: Support multiple nested stage 2 mmu structures
> KVM: arm64: nv: Implement nested Stage-2 page table walk logic
> KVM: arm64: nv: Handle shadow stage 2 page faults
> KVM: arm64: nv: Unmap/flush shadow stage 2 page tables
> KVM: arm64: nv: arch_timer: Support hyp timer emulation
> KVM: arm64: nv: vgic-v3: Take cpu_if pointer directly instead of vcpu
> KVM: arm64: nv: vgic: Emulate the HW bit in software
> KVM: arm64: nv: Add nested GICv3 tracepoints
>
> Dave Martin (1):
> KVM: arm64: Migrate _elx sysreg accessors to msr_s/mrs_s
>
> Jintack Lim (21):
> arm64: Add ARM64_HAS_NESTED_VIRT cpufeature
> KVM: arm64: nv: Add EL2 system registers to vcpu context
> KVM: arm64: nv: Support virtual EL2 exceptions
> KVM: arm64: nv: Inject HVC exceptions to the virtual EL2
> KVM: arm64: nv: Trap SPSR_EL1, ELR_EL1 and VBAR_EL1 from virtual EL2
> KVM: arm64: nv: Trap CPACR_EL1 access in virtual EL2
> KVM: arm64: nv: Set a handler for the system instruction traps
> KVM: arm64: nv: Handle PSCI call via smc from the guest
> KVM: arm64: nv: Respect virtual HCR_EL2.TWX setting
> KVM: arm64: nv: Respect virtual CPTR_EL2.TFP setting
> KVM: arm64: nv: Respect the virtual HCR_EL2.NV bit setting
> KVM: arm64: nv: Respect virtual HCR_EL2.TVM and TRVM settings
> KVM: arm64: nv: Respect the virtual HCR_EL2.NV1 bit setting
> KVM: arm64: nv: Emulate EL12 register accesses from the virtual EL2
> KVM: arm64: nv: Configure HCR_EL2 for nested virtualization
> KVM: arm64: nv: Pretend we only support larger-than-host page sizes
> KVM: arm64: nv: Introduce sys_reg_desc.forward_trap
> KVM: arm64: nv: Rework the system instruction emulation framework
> KVM: arm64: nv: Trap and emulate AT instructions from virtual EL2
> KVM: arm64: nv: Trap and emulate TLBI instructions from virtual EL2
> KVM: arm64: nv: Nested GICv3 Support
>
> Marc Zyngier (17):
> KVM: arm64: Move __load_guest_stage2 to kvm_mmu.h
> KVM: arm64: nv: Reset VMPIDR_EL2 and VPIDR_EL2 to sane values
> KVM: arm64: nv: Handle SPSR_EL2 specially
> KVM: arm64: nv: Refactor vcpu_{read,write}_sys_reg
> KVM: arm64: nv: Don't expose SVE to nested guests
> KVM: arm64: nv: Hide RAS from nested guests
> KVM: arm/arm64: nv: Factor out stage 2 page table data from struct kvm
> KVM: arm64: nv: Move last_vcpu_ran to be per s2 mmu
> KVM: arm64: nv: Don't always start an S2 MMU search from the beginning
> KVM: arm64: nv: Propagate CNTVOFF_EL2 to the virtual EL1 timer
> KVM: arm64: nv: Load timer before the GIC
> KVM: arm64: nv: Implement maintenance interrupt forwarding
> arm64: KVM: nv: Add handling of EL2-specific timer registers
> arm64: KVM: nv: Honor SCTLR_EL2.SPAN on entering vEL2
> arm64: KVM: nv: Handle SCTLR_EL2 RES0/RES1 bits
> arm64: KVM: nv: Restrict S2 RD/WR permissions to match the guest's
> arm64: KVM: nv: Allow userspace to request KVM_ARM_VCPU_NESTED_VIRT
>
> .../admin-guide/kernel-parameters.txt | 4 +
> .../virtual/kvm/devices/arm-vgic-v3.txt | 9 +
> arch/arm/include/asm/kvm_asm.h | 5 +-
> arch/arm/include/asm/kvm_emulate.h | 3 +
> arch/arm/include/asm/kvm_host.h | 31 +-
> arch/arm/include/asm/kvm_hyp.h | 25 +-
> arch/arm/include/asm/kvm_mmu.h | 83 +-
> arch/arm/include/asm/kvm_nested.h | 9 +
> arch/arm/include/uapi/asm/kvm.h | 1 +
> arch/arm/kvm/hyp/switch.c | 11 +-
> arch/arm/kvm/hyp/tlb.c | 13 +-
> arch/arm64/include/asm/cpucaps.h | 3 +-
> arch/arm64/include/asm/esr.h | 4 +-
> arch/arm64/include/asm/kvm_arm.h | 28 +-
> arch/arm64/include/asm/kvm_asm.h | 9 +-
> arch/arm64/include/asm/kvm_coproc.h | 2 +-
> arch/arm64/include/asm/kvm_emulate.h | 157 +-
> arch/arm64/include/asm/kvm_host.h | 105 +-
> arch/arm64/include/asm/kvm_hyp.h | 82 +-
> arch/arm64/include/asm/kvm_mmu.h | 62 +-
> arch/arm64/include/asm/kvm_nested.h | 68 +
> arch/arm64/include/asm/sysreg.h | 143 +-
> arch/arm64/include/uapi/asm/kvm.h | 2 +
> arch/arm64/kernel/cpufeature.c | 26 +
> arch/arm64/kvm/Makefile | 4 +
> arch/arm64/kvm/emulate-nested.c | 223 +++
> arch/arm64/kvm/guest.c | 6 +
> arch/arm64/kvm/handle_exit.c | 76 +-
> arch/arm64/kvm/hyp/Makefile | 1 +
> arch/arm64/kvm/hyp/at.c | 217 +++
> arch/arm64/kvm/hyp/switch.c | 86 +-
> arch/arm64/kvm/hyp/sysreg-sr.c | 267 ++-
> arch/arm64/kvm/hyp/tlb.c | 129 +-
> arch/arm64/kvm/hyp/vgic-v2-cpuif-proxy.c | 2 +-
> arch/arm64/kvm/inject_fault.c | 12 -
> arch/arm64/kvm/nested.c | 551 +++++++
> arch/arm64/kvm/regmap.c | 4 +-
> arch/arm64/kvm/reset.c | 7 +
> arch/arm64/kvm/sys_regs.c | 1460 +++++++++++++++--
> arch/arm64/kvm/sys_regs.h | 6 +
> arch/arm64/kvm/trace.h | 58 +-
> include/kvm/arm_arch_timer.h | 6 +
> include/kvm/arm_vgic.h | 28 +-
> virt/kvm/arm/arch_timer.c | 158 +-
> virt/kvm/arm/arm.c | 62 +-
> virt/kvm/arm/hyp/vgic-v3-sr.c | 35 +-
> virt/kvm/arm/mmio.c | 12 +-
> virt/kvm/arm/mmu.c | 445 +++--
> virt/kvm/arm/trace.h | 6 +-
> virt/kvm/arm/vgic/vgic-init.c | 30 +
> virt/kvm/arm/vgic/vgic-kvm-device.c | 22 +
> virt/kvm/arm/vgic/vgic-nested-trace.h | 137 ++
> virt/kvm/arm/vgic/vgic-v2.c | 10 +-
> virt/kvm/arm/vgic/vgic-v3-nested.c | 236 +++
> virt/kvm/arm/vgic/vgic-v3.c | 40 +-
> virt/kvm/arm/vgic/vgic.c | 74 +-
> 56 files changed, 4683 insertions(+), 612 deletions(-)
> create mode 100644 arch/arm/include/asm/kvm_nested.h
> create mode 100644 arch/arm64/include/asm/kvm_nested.h
> create mode 100644 arch/arm64/kvm/emulate-nested.c
> create mode 100644 arch/arm64/kvm/hyp/at.c
> create mode 100644 arch/arm64/kvm/nested.c
> create mode 100644 virt/kvm/arm/vgic/vgic-nested-trace.h
> create mode 100644 virt/kvm/arm/vgic/vgic-v3-nested.c
>
When working on adding support for EL2 to kvm-unit-tests I was able to trigger
the following warning:

# ./lkvm run -f psci.flat -m 128 -c 8 --console serial --irqchip gicv3 --nested
# lkvm run --firmware psci.flat -m 128 -c 8 --name guest-151
Info: Placing fdt at 0x80200000 - 0x80210000
# Warning: The maximum recommended amount of VCPUs is 4
chr_testdev_init: chr-testdev: can't find a virtio-console
INFO: PSCI version 1.0
PASS: invalid-function
PASS: affinity-info-on
PASS: affinity-info-off
[   24.381266] WARNING: CPU: 3 PID: 160 at
arch/arm64/kvm/../../../virt/kvm/arm/arch_timer.c:170
kvm_timer_irq_can_fire+0xc/0x30
[   24.381366] Modules linked in:
[   24.381466] CPU: 3 PID: 160 Comm: kvm-vcpu-1 Not tainted
5.2.0-rc5-00060-g7dbce63bd1c7 #145
[   24.381566] Hardware name: Foundation-v8A (DT)
[   24.381566] pstate: 40400009 (nZcv daif +PAN -UAO)
[   24.381666] pc : kvm_timer_irq_can_fire+0xc/0x30
[   24.381766] lr : timer_emulate+0x24/0x98
[   24.381766] sp : ffff000013d8b780
[   24.381866] x29: ffff000013d8b780 x28: ffff80087a639b80
[   24.381966] x27: ffff000010ba8648 x26: ffff000010b71b40
[   24.382066] x25: ffff80087a63a100 x24: 0000000000000000
[   24.382111] x23: 000080086ca54000 x22: ffff0000100ce260
[   24.382166] x21: ffff800875e7c918 x20: ffff800875e7a800
[   24.382275] x19: ffff800875e7ca08 x18: 0000000000000000
[   24.382366] x17: 0000000000000000 x16: 0000000000000000
[   24.382466] x15: 0000000000000000 x14: 0000000000002118
[   24.382566] x13: 0000000000002190 x12: 0000000000002280
[   24.382566] x11: 0000000000002208 x10: 0000000000000040
[   24.382666] x9 : ffff000012dc3b38 x8 : 0000000000000000
[   24.382766] x7 : 0000000000000000 x6 : ffff80087ac00248
[   24.382866] x5 : 000080086ca54000 x4 : 0000000000002118
[   24.382966] x3 : eeeeeeeeeeeeeeef x2 : ffff800875e7c918
[   24.383066] x1 : 0000000000000001 x0 : ffff800875e7ca08
[   24.383066] Call trace:
[   24.383166]  kvm_timer_irq_can_fire+0xc/0x30
[   24.383266]  kvm_timer_vcpu_load+0x9c/0x1a0
[   24.383366]  kvm_arch_vcpu_load+0xb0/0x1f0
[   24.383366]  kvm_sched_in+0x1c/0x28
[   24.383466]  finish_task_switch+0xd8/0x1d8
[   24.383566]  __schedule+0x248/0x4a0
[   24.383666]  preempt_schedule_irq+0x60/0x90
[   24.383666]  el1_irq+0xd0/0x180
[   24.383766]  kvm_handle_guest_abort+0x0/0x3a0
[   24.383866]  kvm_arch_vcpu_ioctl_run+0x41c/0x688
[   24.383866]  kvm_vcpu_ioctl+0x4c0/0x838
[   24.383966]  do_vfs_ioctl+0xb8/0x878
[   24.384077]  ksys_ioctl+0x84/0x90
[   24.384166]  __arm64_sys_ioctl+0x18/0x28
[   24.384166]  el0_svc_common.constprop.0+0xb0/0x168
[   24.384266]  el0_svc_handler+0x28/0x78
[   24.384366]  el0_svc+0x8/0xc
[   24.384366] ---[ end trace 37a32293e43ac12c ]---
[   24.384666] WARNING: CPU: 3 PID: 160 at
arch/arm64/kvm/../../../virt/kvm/arm/arch_timer.c:170
kvm_timer_irq_can_fire+0xc/0x30
[   24.384766] Modules linked in:
[   24.384866] CPU: 3 PID: 160 Comm: kvm-vcpu-1 Tainted: G W
5.2.0-rc5-00060-g7dbce63bd1c7 #145
[   24.384966] Hardware name: Foundation-v8A (DT)
[   24.384966] pstate: 40400009 (nZcv daif +PAN -UAO)
[   24.385066] pc : kvm_timer_irq_can_fire+0xc/0x30
[   24.385166] lr : timer_emulate+0x24/0x98
[   24.385166] sp : ffff000013d8b780
[   24.385266] x29: ffff000013d8b780 x28: ffff80087a639b80
[   24.385366] x27: ffff000010ba8648 x26: ffff000010b71b40
[   24.385466] x25: ffff80087a63a100 x24: 0000000000000000
[   24.385466] x23: 000080086ca54000 x22: ffff0000100ce260
[   24.385566] x21: ffff800875e7c918 x20: ffff800875e7a800
[   24.385666] x19: ffff800875e7ca80 x18: 0000000000000000
[   24.385766] x17: 0000000000000000 x16: 0000000000000000
[   24.385866] x15: 0000000000000000 x14: 0000000000002118
[   24.385966] x13: 0000000000002190 x12: 0000000000002280
[   24.385966] x11: 0000000000002208 x10: 0000000000000040
[   24.386066] x9 : ffff000012dc3b38 x8 : 0000000000000000
[   24.386166] x7 : 0000000000000000 x6 : ffff80087ac00248
[   24.386266] x5 : 000080086ca54000 x4 : 0000000000002118
[   24.386366] x3 : eeeeeeeeeeeeeeef x2 : ffff800875e7c918
[   24.386466] x1 : 0000000000000001 x0 : ffff800875e7ca80
[   24.386466] Call trace:
[   24.386566]  kvm_timer_irq_can_fire+0xc/0x30
[   24.386666]  kvm_timer_vcpu_load+0xa8/0x1a0
[   24.386666]  kvm_arch_vcpu_load+0xb0/0x1f0
[   24.386898]  kvm_sched_in+0x1c/0x28
[   24.386966]  finish_task_switch+0xd8/0x1d8
[   24.387166]  __schedule+0x248/0x4a0
[   24.387354]  preempt_schedule_irq+0x60/0x90
[   24.387366]  el1_irq+0xd0/0x180
[   24.387466]  kvm_handle_guest_abort+0x0/0x3a0
[   24.387566]  kvm_arch_vcpu_ioctl_run+0x41c/0x688
[   24.387566]  kvm_vcpu_ioctl+0x4c0/0x838
[   24.387666]  do_vfs_ioctl+0xb8/0x878
[   24.387766]  ksys_ioctl+0x84/0x90
[   24.387866]  __arm64_sys_ioctl+0x18/0x28
[   24.387866]  el0_svc_common.constprop.0+0xb0/0x168
[   24.387966]  el0_svc_handler+0x28/0x78
[   24.388066]  el0_svc+0x8/0xc
[   24.388066] ---[ end trace 37a32293e43ac12d ]---
PASS: cpu-on
SUMMARY: 4 te[   24.390266] WARNING: CPU: 3 PID: 160 at
arch/arm64/kvm/../../../virt/kvm/arm/arch_timer.c:170
kvm_timer_irq_can_fire+0xc/0x30
s[   24.390366] Modules linked in:
ts[   24.390366] CPU: 3 PID: 160 Comm: kvm-vcpu-1 Tainted: G W
5.2.0-rc5-00060-g7dbce63bd1c7 #145
[   24.390566] Hardware name: Foundation-v8A (DT)

[   24.390795] pstate: 40400009 (nZcv daif +PAN -UAO)
[   24.390866] pc : kvm_timer_irq_can_fire+0xc/0x30
[   24.390966] lr : timer_emulate+0x24/0x98
[   24.391066] sp : ffff000013d8b780
[   24.391066] x29: ffff000013d8b780 x28: ffff80087a639b80
[   24.391166] x27: ffff000010ba8648 x26: ffff000010b71b40
[   24.391266] x25: ffff80087a63a100 x24: 0000000000000000
[   24.391366] x23: 000080086ca54000 x22: 0000000000000003
[   24.391466] x21: ffff800875e7c918 x20: ffff800875e7a800
[   24.391466] x19: ffff800875e7ca08 x18: 0000000000000000
[   24.391566] x17: 0000000000000000 x16: 0000000000000000
[   24.391666] x15: 0000000000000000 x14: 0000000000002118
[   24.391766] x13: 0000000000002190 x12: 0000000000002280
[   24.391866] x11: 0000000000002208 x10: 0000000000000040
[   24.391942] x9 : ffff000012dc3b38 x8 : 0000000000000000
[   24.391966] x7 : 0000000000000000 x6 : ffff80087ac00248
[   24.392066] x5 : 000080086ca54000 x4 : 0000000000002118
[   24.392166] x3 : eeeeeeeeeeeeeeef x2 : ffff800875e7c918
[   24.392269] x1 : 0000000000000001 x0 : ffff800875e7ca08
[   24.392366] Call trace:
[   24.392433]  kvm_timer_irq_can_fire+0xc/0x30
[   24.392466]  kvm_timer_vcpu_load+0x9c/0x1a0
[   24.392597]  kvm_arch_vcpu_load+0xb0/0x1f0
[   24.392666]  kvm_sched_in+0x1c/0x28
[   24.392766]  finish_task_switch+0xd8/0x1d8
[   24.392766]  __schedule+0x248/0x4a0
[   24.392866]  preempt_schedule_irq+0x60/0x90
[   24.392966]  el1_irq+0xd0/0x180
[   24.392966]  kvm_handle_guest_abort+0x0/0x3a0
[   24.393066]  kvm_arch_vcpu_ioctl_run+0x41c/0x688
[   24.393166]  kvm_vcpu_ioctl+0x4c0/0x838
[   24.393266]  do_vfs_ioctl+0xb8/0x878
[   24.393266]  ksys_ioctl+0x84/0x90
[   24.393366]  __arm64_sys_ioctl+0x18/0x28
[   24.393466]  el0_svc_common.constprop.0+0xb0/0x168
[   24.393566]  el0_svc_handler+0x28/0x78
[   24.393566]  el0_svc+0x8/0xc
[   24.393666] ---[ end trace 37a32293e43ac12e ]---
[   24.393866] WARNING: CPU: 3 PID: 160 at
arch/arm64/kvm/../../../virt/kvm/arm/arch_timer.c:170
kvm_timer_irq_can_fire+0xc/0x30
[   24.394066] Modules linked in:
[   24.394266] CPU: 3 PID: 160 Comm: kvm-vcpu-1 Tainted: G W
5.2.0-rc5-00060-g7dbce63bd1c7 #145
[   24.394366] Hardware name: Foundation-v8A (DT)
[   24.394466] pstate: 40400009 (nZcv daif +PAN -UAO)
[   24.394466] pc : kvm_timer_irq_can_fire+0xc/0x30
[   24.394566] lr : timer_emulate+0x24/0x98
[   24.394666] sp : ffff000013d8b780
[   24.394727] x29: ffff000013d8b780 x28: ffff80087a639b80
[   24.394766] x27: ffff000010ba8648 x26: ffff000010b71b40
[   24.394866] x25: ffff80087a63a100 x24: 0000000000000000
[   24.394966] x23: 000080086ca54000 x22: 0000000000000003
[   24.394966] x21: ffff800875e7c918 x20: ffff800875e7a800
[   24.395066] x19: ffff800875e7ca80 x18: 0000000000000000
[   24.395166] x17: 0000000000000000 x16: 0000000000000000
[   24.395266] x15: 0000000000000000 x14: 0000000000002118
[   24.395383] x13: 0000000000002190 x12: 0000000000002280
[   24.395466] x11: 0000000000002208 x10: 0000000000000040
[   24.395547] x9 : ffff000012dc3b38 x8 : 0000000000000000
[   24.395666] x7 : 0000000000000000 x6 : ffff80087ac00248
[   24.395866] x5 : 000080086ca54000 x4 : 0000000000002118
[   24.395966] x3 : eeeeeeeeeeeeeeef x2 : ffff800875e7c918
[   24.396066] x1 : 0000000000000001 x0 : ffff800875e7ca80
[   24.396066] Call trace:
[   24.396166]  kvm_timer_irq_can_fire+0xc/0x30
[   24.396266]  kvm_timer_vcpu_load+0xa8/0x1a0
[   24.396366]  kvm_arch_vcpu_load+0xb0/0x1f0
[   24.396366]  kvm_sched_in+0x1c/0x28
[   24.396466]  finish_task_switch+0xd8/0x1d8
[   24.396566]  __schedule+0x248/0x4a0
[   24.396666]  preempt_schedule_irq+0x60/0x90
[   24.396666]  el1_irq+0xd0/0x180
[   24.396766]  kvm_handle_guest_abort+0x0/0x3a0
[   24.396866]  kvm_arch_vcpu_ioctl_run+0x41c/0x688
[   24.396866]  kvm_vcpu_ioctl+0x4c0/0x838
[   24.397021]  do_vfs_ioctl+0xb8/0x878
[   24.397066]  ksys_ioctl+0x84/0x90
[   24.397166]  __arm64_sys_ioctl+0x18/0x28
[   24.397348]  el0_svc_common.constprop.0+0xb0/0x168
[   24.397366]  el0_svc_handler+0x28/0x78
[   24.397566]  el0_svc+0x8/0xc
[   24.397676] ---[ end trace 37a32293e43ac12f ]---

# KVM compatibility warning.
virtio-9p device was not detected.
While you have requested a virtio-9p device, the guest kernel did not
initialize it.
Please make sure that the guest kernel was compiled with
CONFIG_NET_9P_VIRTIO=y enabled in .config.

# KVM compatibility warning.
virtio-net device was not detected.
While you have requested a virtio-net device, the guest kernel did not
initialize it.
Please make sure that the guest kernel was compiled with CONFIG_VIRTIO_NET=y
enabled in .config.

These are the changes that I made to kvm-unit-tests (the diff can be applied on
top of upstream master, 2130fd4154ad ("tscdeadline_latency: Check condition
first before loop")):

diff --git a/arm/cstart64.S b/arm/cstart64.S
index b0e8baa1a23a..a7631b5a1801 100644
--- a/arm/cstart64.S
+++ b/arm/cstart64.S
@@ -51,6 +51,17 @@ start:
b 1b

1:
+ mrs x4, CurrentEL
+ cmp x4, CurrentEL_EL2
+ b.ne 1f
+ mrs x4, mpidr_el1
+ msr vmpidr_el2, x4
+ mrs x4, midr_el1
+ msr vpidr_el2, x4
+ ldr x4, =(HCR_EL2_TGE | HCR_EL2_E2H)
+ msr hcr_el2, x4
+ isb
+1:
/* set up stack */
mov x4, #1
msr spsel, x4
@@ -101,6 +112,17 @@ get_mmu_off:

.globl secondary_entry
secondary_entry:
+ mrs x0, CurrentEL
+ cmp x0, CurrentEL_EL2
+ b.ne 1f
+ mrs x0, mpidr_el1
+ msr vmpidr_el2, x0
+ mrs x0, midr_el1
+ msr vpidr_el2, x0
+ ldr x0, =(HCR_EL2_TGE | HCR_EL2_E2H)
+ msr hcr_el2, x0
+ isb
+1:
/* Enable FP/ASIMD */
mov x0, #(3 << 20)
msr cpacr_el1, x0
diff --git a/lib/arm/asm/psci.h b/lib/arm/asm/psci.h
index 7b956bf5987d..07297a27e0ce 100644
--- a/lib/arm/asm/psci.h
+++ b/lib/arm/asm/psci.h
@@ -3,6 +3,15 @@
#include <libcflat.h>
#include <linux/psci.h>

+enum psci_conduit {
+ PSCI_CONDUIT_HVC,
+ PSCI_CONDUIT_SMC,
+};
+
+extern void psci_init(void);
+extern void psci_set_conduit(enum psci_conduit conduit);
+extern enum psci_conduit psci_get_conduit(void);
+
extern int psci_invoke(unsigned long function_id, unsigned long arg0,
unsigned long arg1, unsigned long arg2);
extern int psci_cpu_on(unsigned long cpuid, unsigned long entry_point);
diff --git a/lib/arm/psci.c b/lib/arm/psci.c
index c3d399064ae3..20ad4b944738 100644
--- a/lib/arm/psci.c
+++ b/lib/arm/psci.c
@@ -6,13 +6,14 @@
*
* This work is licensed under the terms of the GNU LGPL, version 2.
*/
+#include <devicetree.h>
+#include <string.h>
#include <asm/psci.h>
#include <asm/setup.h>
#include <asm/page.h>
#include <asm/smp.h>

-__attribute__((noinline))
-int psci_invoke(unsigned long function_id, unsigned long arg0,
+static int psci_invoke_hvc(unsigned long function_id, unsigned long arg0,
unsigned long arg1, unsigned long arg2)
{
asm volatile(
@@ -22,6 +23,63 @@ int psci_invoke(unsigned long function_id, unsigned long arg0,
return function_id;
}

+static int psci_invoke_smc(unsigned long function_id, unsigned long arg0,
+ unsigned long arg1, unsigned long arg2)
+{
+ asm volatile(
+ "smc #0"
+ : "+r" (function_id)
+ : "r" (arg0), "r" (arg1), "r" (arg2));
+ return function_id;
+}
+
+/*
+ * Initialize to something sensible, so the exit fallback psci_system_off still
+ * works before calling psci_init when booted at EL1.
+ */
+static enum psci_conduit psci_conduit = PSCI_CONDUIT_HVC;
+static int (*psci_fn)(unsigned long, unsigned long, unsigned long,
+ unsigned long) = &psci_invoke_hvc;
+
+void psci_set_conduit(enum psci_conduit conduit)
+{
+ psci_conduit = conduit;
+ if (conduit == PSCI_CONDUIT_HVC)
+ psci_fn = &psci_invoke_hvc;
+ else
+ psci_fn = &psci_invoke_smc;
+}
+
+enum psci_conduit psci_get_conduit(void)
+{
+ return psci_conduit;
+}
+
+int psci_invoke(unsigned long function_id, unsigned long arg0,
+ unsigned long arg1, unsigned long arg2)
+{
+ return psci_fn(function_id, arg0, arg1, arg2);
+}
+
+void psci_init(void)
+{
+ const char *conduit;
+ int ret;
+
+ ret = dt_get_psci_conduit(&conduit);
+ assert(ret == 0 || ret == -FDT_ERR_NOTFOUND);
+
+ if (ret == -FDT_ERR_NOTFOUND)
+ conduit = "hvc";
+
+ assert(strcmp(conduit, "hvc") == 0 || strcmp(conduit, "smc") == 0);
+
+ if (strcmp(conduit, "hvc") == 0)
+ psci_set_conduit(PSCI_CONDUIT_HVC);
+ else
+ psci_set_conduit(PSCI_CONDUIT_SMC);
+}
+
int psci_cpu_on(unsigned long cpuid, unsigned long entry_point)
{
#ifdef __arm__
diff --git a/lib/arm/setup.c b/lib/arm/setup.c
index 4f02fca85607..e0dc9e4801b0 100644
--- a/lib/arm/setup.c
+++ b/lib/arm/setup.c
@@ -21,6 +21,7 @@
#include <asm/setup.h>
#include <asm/page.h>
#include <asm/smp.h>
+#include <asm/psci.h>

#include "io.h"

@@ -164,7 +165,11 @@ void setup(const void *fdt)
freemem += initrd_size;
}

- /* call init functions */
+ /*
+ * call init functions. psci_init goes first so psci_system_off fallback
+ * works in case of an assert failure
+ */
+ psci_init();
mem_init(PAGE_ALIGN((unsigned long)freemem));
cpu_init();

diff --git a/lib/arm64/asm/processor.h b/lib/arm64/asm/processor.h
index 1d9223f728a5..18c5d29ddd1f 100644
--- a/lib/arm64/asm/processor.h
+++ b/lib/arm64/asm/processor.h
@@ -16,6 +16,9 @@
#define SCTLR_EL1_A (1 << 1)
#define SCTLR_EL1_M (1 << 0)

+#define HCR_EL2_TGE (1 << 27)
+#define HCR_EL2_E2H (1 << 34)
+
#ifndef __ASSEMBLY__
#include <asm/ptrace.h>
#include <asm/esr.h>
diff --git a/lib/devicetree.c b/lib/devicetree.c
index 2b89178a109b..4e684c7100b2 100644
--- a/lib/devicetree.c
+++ b/lib/devicetree.c
@@ -263,6 +263,27 @@ int dt_get_bootargs(const char **bootargs)
return 0;
}

+int dt_get_psci_conduit(const char **conduit)
+{
+ const struct fdt_property *prop;
+ int node, len;
+
+ *conduit = NULL;
+
+ node = fdt_node_offset_by_compatible(fdt, -1, "arm,psci-0.2");
+ if (node < 0)
+ return node;
+
+ prop = fdt_get_property(fdt, node, "method", &len);
+ if (!prop)
+ return len;
+ if (len < 4)
+ return -FDT_ERR_NOTFOUND;
+
+ *conduit = prop->data;
+ return 0;
+}
+
int dt_get_default_console_node(void)
{
const struct fdt_property *prop;
diff --git a/lib/devicetree.h b/lib/devicetree.h
index 93c7ebc63bd8..236035eb777d 100644
--- a/lib/devicetree.h
+++ b/lib/devicetree.h
@@ -211,6 +211,15 @@ extern int dt_get_reg(int fdtnode, int regidx, struct
dt_reg *reg);
extern int dt_get_bootargs(const char **bootargs);

/*
+ * dt_get_psci_conduit gets the conduit for PSCI function invocations from
+ * /psci/method
+ * returns
+ * - zero on success
+ * - a negative FDT_ERR_* value on failure, and @conduit will be set to null
+ */
+extern int dt_get_psci_conduit(const char **conduit);
+
+/*
* dt_get_default_console_node gets the node of the path stored in
* /chosen/stdout-path (or the deprecated /chosen/linux,stdout-path)
* returns

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