[PATCH 04/20] arm64: KVM: Allow the main HYP code to use the init hyp stub implementation
From: Marc Zyngier <hidden>
Date: 2017-02-17 15:44:13
Also in:
kvm, kvmarm
Subsystem:
arm64 port (aarch64 architecture), kernel virtual machine for arm64 (kvm/arm64), the rest · Maintainers:
Catalin Marinas, Will Deacon, Marc Zyngier, Oliver Upton, Linus Torvalds
We now have a full hyp-stub implementation in the KVM init code, but the main KVM code only supports HVC_GET_VECTORS, which is not enough. Instead of reinventing the wheel, let's reuse the init implementation by branching to the idmap page when called with a hyp-stub hypercall. Signed-off-by: Marc Zyngier <redacted> --- arch/arm64/kvm/hyp/hyp-entry.S | 24 +++++++++++++++++++----- 1 file changed, 19 insertions(+), 5 deletions(-)
diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S
index 5e9052f087f2..21eeb2552f33 100644
--- a/arch/arm64/kvm/hyp/hyp-entry.S
+++ b/arch/arm64/kvm/hyp/hyp-entry.S@@ -87,10 +87,24 @@ alternative_endif /* Here, we're pretty sure the host called HVC. */ ldp x0, x1, [sp], #16 - cmp x0, #HVC_GET_VECTORS - b.ne 1f - mrs x0, vbar_el2 - b 2f + /* Check for a stub HVC call */ + cmp x0, #HVC_STUB_HCALL_NR + b.hs 1f + + /* + * Compute the idmap address of __kvm_handle_stub_hvc and + * jump there. Since we use kimage_voffset, do not use the + * HYP VA for __kvm_handle_stub_hvc, but the kernel VA instead + * (by loading it from the constant pool). + * + * Preserve x0-x4, which may contain stub parameters. + */ + ldr x5, =__kvm_handle_stub_hvc + ldr_l x6, kimage_voffset + + /* x5 = __pa(x5) */ + sub x5, x5, x6 + br x5 1: /*
@@ -99,7 +113,7 @@ alternative_endif kern_hyp_va x0 do_el2_call -2: eret + eret el1_trap: /*
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2.11.0