KVM: arm64: nVHE: Migrate hyp interface to SMCCC

Rather than passing arbitrary function pointers to run at hyp, define
and equivalent set of SMCCC functions.

Since the SMCCC functions are strongly tied to the original function
prototypes, it is not expected for the host to ever call an invalid ID
but a warning is raised if this does ever occur.

As __kvm_vcpu_run is used for every switch between the host and a guest,
it is explicitly singled out to be identified before the other function
IDs to improve the performance of the hot path.

Signed-off-by: Andrew Scull <ascull@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200915104643.2543892-18-ascull@google.com

1 files changed, 94 insertions, 13 deletions

diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
index 570c3896f42e..41aaf038599a 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
@@ -12,25 +12,106 @@
 #include <asm/kvm_hyp.h>
 #include <asm/kvm_mmu.h>
 
-typedef unsigned long (*hypcall_fn_t)
-	(unsigned long, unsigned long, unsigned long);
+#include <kvm/arm_hypercalls.h>
+
+static void handle_host_hcall(unsigned long func_id,
+			      struct kvm_cpu_context *host_ctxt)
+{
+	unsigned long ret = 0;
+
+	switch (func_id) {
+	case KVM_HOST_SMCCC_FUNC(__kvm_vcpu_run): {
+		unsigned long r1 = host_ctxt->regs.regs[1];
+		struct kvm_vcpu *vcpu = (struct kvm_vcpu *)r1;
+
+		ret = __kvm_vcpu_run(vcpu);
+		break;
+	}
+	case KVM_HOST_SMCCC_FUNC(__kvm_flush_vm_context):
+		__kvm_flush_vm_context();
+		break;
+	case KVM_HOST_SMCCC_FUNC(__kvm_tlb_flush_vmid_ipa): {
+		unsigned long r1 = host_ctxt->regs.regs[1];
+		struct kvm_s2_mmu *mmu = (struct kvm_s2_mmu *)r1;
+		phys_addr_t ipa = host_ctxt->regs.regs[2];
+		int level = host_ctxt->regs.regs[3];
+
+		__kvm_tlb_flush_vmid_ipa(mmu, ipa, level);
+		break;
+	}
+	case KVM_HOST_SMCCC_FUNC(__kvm_tlb_flush_vmid): {
+		unsigned long r1 = host_ctxt->regs.regs[1];
+		struct kvm_s2_mmu *mmu = (struct kvm_s2_mmu *)r1;
+
+		__kvm_tlb_flush_vmid(mmu);
+		break;
+	}
+	case KVM_HOST_SMCCC_FUNC(__kvm_tlb_flush_local_vmid): {
+		unsigned long r1 = host_ctxt->regs.regs[1];
+		struct kvm_s2_mmu *mmu = (struct kvm_s2_mmu *)r1;
+
+		__kvm_tlb_flush_local_vmid(mmu);
+		break;
+	}
+	case KVM_HOST_SMCCC_FUNC(__kvm_timer_set_cntvoff): {
+		u64 cntvoff = host_ctxt->regs.regs[1];
+
+		__kvm_timer_set_cntvoff(cntvoff);
+		break;
+	}
+	case KVM_HOST_SMCCC_FUNC(__kvm_enable_ssbs):
+		__kvm_enable_ssbs();
+		break;
+	case KVM_HOST_SMCCC_FUNC(__vgic_v3_get_ich_vtr_el2):
+		ret = __vgic_v3_get_ich_vtr_el2();
+		break;
+	case KVM_HOST_SMCCC_FUNC(__vgic_v3_read_vmcr):
+		ret = __vgic_v3_read_vmcr();
+		break;
+	case KVM_HOST_SMCCC_FUNC(__vgic_v3_write_vmcr): {
+		u32 vmcr = host_ctxt->regs.regs[1];
+
+		__vgic_v3_write_vmcr(vmcr);
+		break;
+	}
+	case KVM_HOST_SMCCC_FUNC(__vgic_v3_init_lrs):
+		__vgic_v3_init_lrs();
+		break;
+	case KVM_HOST_SMCCC_FUNC(__kvm_get_mdcr_el2):
+		ret = __kvm_get_mdcr_el2();
+		break;
+	case KVM_HOST_SMCCC_FUNC(__vgic_v3_save_aprs): {
+		unsigned long r1 = host_ctxt->regs.regs[1];
+		struct vgic_v3_cpu_if *cpu_if = (struct vgic_v3_cpu_if *)r1;
+
+		__vgic_v3_save_aprs(cpu_if);
+		break;
+	}
+	case KVM_HOST_SMCCC_FUNC(__vgic_v3_restore_aprs): {
+		unsigned long r1 = host_ctxt->regs.regs[1];
+		struct vgic_v3_cpu_if *cpu_if = (struct vgic_v3_cpu_if *)r1;
+
+		__vgic_v3_restore_aprs(cpu_if);
+		break;
+	}
+	default:
+		/* Invalid host HVC. */
+		host_ctxt->regs.regs[0] = SMCCC_RET_NOT_SUPPORTED;
+		return;
+	}
+
+	host_ctxt->regs.regs[0] = SMCCC_RET_SUCCESS;
+	host_ctxt->regs.regs[1] = ret;
+}
 
 void handle_trap(struct kvm_cpu_context *host_ctxt)
 {
 	u64 esr = read_sysreg_el2(SYS_ESR);
-	hypcall_fn_t func;
-	unsigned long ret;
+	unsigned long func_id;
 
 	if (ESR_ELx_EC(esr) != ESR_ELx_EC_HVC64)
 		hyp_panic();
 
-	/*
-	 * __kvm_call_hyp takes a pointer in the host address space and
-	 * up to three arguments.
-	 */
-	func = (hypcall_fn_t)kern_hyp_va(host_ctxt->regs.regs[0]);
-	ret = func(host_ctxt->regs.regs[1],
-		   host_ctxt->regs.regs[2],
-		   host_ctxt->regs.regs[3]);
-	host_ctxt->regs.regs[0] = ret;
+	func_id = host_ctxt->regs.regs[0];
+	handle_host_hcall(func_id, host_ctxt);
 }