diff options
| author | Marc Zyngier <maz@kernel.org> | 2023-04-05 12:48:58 +0100 |
|---|---|---|
| committer | Marc Zyngier <maz@kernel.org> | 2023-04-05 19:20:23 +0100 |
| commit | 0e5c9a9d6548e9b178d4696c696ae4a21c39ae58 (patch) | |
| tree | edaae95c99c0540db8de44a759e8f5242be57e68 /arch | |
| parent | 60e7dade498eb881bcdf0d9a420c97625f73acc1 (diff) | |
KVM: arm64: Expose SMC/HVC width to userspace
When returning to userspace to handle a SMCCC call, we consistently
set PC to point to the instruction immediately after the HVC/SMC.
However, should userspace need to know the exact address of the
trapping instruction, it needs to know about the *size* of that
instruction. For AArch64, this is pretty easy. For AArch32, this
is a bit more funky, as Thumb has 16bit encodings for both HVC
and SMC.
Expose this to userspace with a new flag that directly derives
from ESR_EL2.IL. Also update the documentation to reflect the PC
state at the point of exit.
Finally, this fixes a small buglet where the hypercall.{args,ret}
fields would not be cleared on exit, and could contain some
random junk.
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/86pm8iv8tj.wl-maz@kernel.org
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm64/include/uapi/asm/kvm.h | 3 | ||||
| -rw-r--r-- | arch/arm64/kvm/hypercalls.c | 16 |
2 files changed, 13 insertions, 6 deletions
diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h index 3dcfa4bfdf83..b1c1edf85480 100644 --- a/arch/arm64/include/uapi/asm/kvm.h +++ b/arch/arm64/include/uapi/asm/kvm.h @@ -491,7 +491,8 @@ struct kvm_smccc_filter { }; /* arm64-specific KVM_EXIT_HYPERCALL flags */ -#define KVM_HYPERCALL_EXIT_SMC (1U << 0) +#define KVM_HYPERCALL_EXIT_SMC (1U << 0) +#define KVM_HYPERCALL_EXIT_16BIT (1U << 1) #endif diff --git a/arch/arm64/kvm/hypercalls.c b/arch/arm64/kvm/hypercalls.c index 9a35d6d18193..3b6523f25afc 100644 --- a/arch/arm64/kvm/hypercalls.c +++ b/arch/arm64/kvm/hypercalls.c @@ -222,13 +222,19 @@ static void kvm_prepare_hypercall_exit(struct kvm_vcpu *vcpu, u32 func_id) { u8 ec = ESR_ELx_EC(kvm_vcpu_get_esr(vcpu)); struct kvm_run *run = vcpu->run; - - run->exit_reason = KVM_EXIT_HYPERCALL; - run->hypercall.nr = func_id; - run->hypercall.flags = 0; + u64 flags = 0; if (ec == ESR_ELx_EC_SMC32 || ec == ESR_ELx_EC_SMC64) - run->hypercall.flags |= KVM_HYPERCALL_EXIT_SMC; + flags |= KVM_HYPERCALL_EXIT_SMC; + + if (!kvm_vcpu_trap_il_is32bit(vcpu)) + flags |= KVM_HYPERCALL_EXIT_16BIT; + + run->exit_reason = KVM_EXIT_HYPERCALL; + run->hypercall = (typeof(run->hypercall)) { + .nr = func_id, + .flags = flags, + }; } int kvm_smccc_call_handler(struct kvm_vcpu *vcpu) |