[PATCH v4 07/17] KVM: arm64: Add PKVM_HYP_REQ_HYP_ALLOC request

[Vincent Donnefort]

Introduce a new pkvm_hyp_request type asking the host to top up the pKVM
heap allocator.

Tested-by: Fuad Tabba <fuad.tabba at linux.dev>
Signed-off-by: Vincent Donnefort <vdonnefort at google.com>

diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
index 043495f7fc78..b77acfd7d1c8 100644
--- a/arch/arm64/include/asm/kvm_asm.h
+++ b/arch/arm64/include/asm/kvm_asm.h
@@ -89,6 +89,7 @@ enum __kvm_host_smccc_func {
 	__KVM_HOST_SMCCC_FUNC___vgic_v3_restore_vmcr_aprs,
 	__KVM_HOST_SMCCC_FUNC___vgic_v5_save_apr,
 	__KVM_HOST_SMCCC_FUNC___vgic_v5_restore_vmcr_apr,
+	__KVM_HOST_SMCCC_FUNC___pkvm_hyp_topup,
 
 	MARKER(__KVM_HOST_SMCCC_FUNC_PKVM_ONLY),
 
diff --git a/arch/arm64/include/asm/kvm_pkvm.h b/arch/arm64/include/asm/kvm_pkvm.h
index 6c2497047f8d..99daa985856f 100644
--- a/arch/arm64/include/asm/kvm_pkvm.h
+++ b/arch/arm64/include/asm/kvm_pkvm.h
@@ -17,6 +17,10 @@
 
 #define HYP_MEMBLOCK_REGIONS 128
 
+enum pkvm_topup_id {
+	PKVM_TOPUP_HYP_ALLOC,
+};
+
 int pkvm_init_host_vm(struct kvm *kvm, unsigned long type);
 int pkvm_create_hyp_vm(struct kvm *kvm);
 bool pkvm_hyp_vm_is_created(struct kvm *kvm);
@@ -201,6 +205,7 @@ struct pkvm_mapping {
 
 enum pkvm_hyp_req_type {
 	PKVM_HYP_NO_REQ = 0,
+	PKVM_HYP_REQ_HYP_ALLOC,
 	__PKVM_HYP_REQ_TYPE_MAX,
 };
 
@@ -222,9 +227,13 @@ struct pkvm_hyp_req {
 
 static inline size_t pkvm_hyp_req_arg_size(u8 type)
 {
+	struct pkvm_hyp_req *req;
+
 	switch (type) {
 	case PKVM_HYP_NO_REQ:
 		return 0;
+	case PKVM_HYP_REQ_HYP_ALLOC:
+		return sizeof(req->mem);
 	default:
 		WARN_ON(1);
 	}
diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
index d3c69de698f4..439b91fc8aec 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
@@ -15,6 +15,7 @@
 #include <asm/kvm_hypevents.h>
 #include <asm/kvm_mmu.h>
 
+#include <nvhe/alloc.h>
 #include <nvhe/ffa.h>
 #include <nvhe/mem_protect.h>
 #include <nvhe/mm.h>
@@ -632,6 +633,30 @@ static void handle___pkvm_finalize_teardown_vm(struct kvm_cpu_context *host_ctxt
 	cpu_reg(host_ctxt, 1) = __pkvm_finalize_teardown_vm(handle);
 }
 
+static void handle___pkvm_hyp_topup(struct kvm_cpu_context *host_ctxt)
+{
+	DECLARE_REG(enum pkvm_topup_id, id, host_ctxt, 1);
+	DECLARE_REG(phys_addr_t, head, host_ctxt, 2);
+	DECLARE_REG(unsigned long, nr_pages, host_ctxt, 3);
+	struct kvm_hyp_memcache host_mc = {
+		.head = head,
+		.nr_pages = nr_pages,
+	};
+	int ret;
+
+	switch (id) {
+	case PKVM_TOPUP_HYP_ALLOC:
+		ret = hyp_alloc_topup(&host_mc);
+		break;
+	default:
+		ret = -EINVAL;
+	}
+
+	cpu_reg(host_ctxt, 1) = ret;
+	cpu_reg(host_ctxt, 2) = host_mc.head;
+	cpu_reg(host_ctxt, 3) = host_mc.nr_pages;
+}
+
 static void handle___tracing_load(struct kvm_cpu_context *host_ctxt)
 {
 	DECLARE_REG(unsigned long, desc_hva, host_ctxt, 1);
@@ -740,6 +765,7 @@ static const hcall_t host_hcall[] = {
 	HANDLE_FUNC(__vgic_v3_restore_vmcr_aprs),
 	HANDLE_FUNC(__vgic_v5_save_apr),
 	HANDLE_FUNC(__vgic_v5_restore_vmcr_apr),
+	HANDLE_FUNC(__pkvm_hyp_topup),
 
 	HANDLE_FUNC(__pkvm_host_share_hyp),
 	HANDLE_FUNC(__pkvm_host_unshare_hyp),
diff --git a/arch/arm64/kvm/pkvm.c b/arch/arm64/kvm/pkvm.c
index a626978dc91f..d26e7435d34d 100644
--- a/arch/arm64/kvm/pkvm.c
+++ b/arch/arm64/kvm/pkvm.c
@@ -88,6 +88,33 @@ void __init kvm_hyp_reserve(void)
 		 hyp_mem_base);
 }
 
+static int pkvm_hyp_topup(enum pkvm_topup_id id, unsigned long nr_pages)
+{
+	struct kvm_hyp_memcache mc;
+	struct arm_smccc_res res;
+	int ret;
+
+	init_hyp_memcache(&mc);
+	ret = topup_hyp_memcache(&mc, nr_pages);
+	if (ret)
+		goto err;
+
+	arm_smccc_1_1_hvc(KVM_HOST_SMCCC_FUNC(__pkvm_hyp_topup), id, mc.head,
+			  mc.nr_pages, &res);
+	if (WARN_ON_ONCE(res.a0 != SMCCC_RET_SUCCESS)) {
+		ret = -EINVAL;
+		goto err;
+	}
+
+	ret = res.a1;
+	mc.head = res.a2;
+	mc.nr_pages = res.a3;
+
+err:
+	free_hyp_memcache(&mc);
+	return ret;
+}
+
 static void __pkvm_destroy_hyp_vm(struct kvm *kvm)
 {
 	if (pkvm_hyp_vm_is_created(kvm)) {
@@ -599,6 +626,9 @@ static int pkvm_handle_hyp_req(struct pkvm_hyp_req *req)
 	int ret = -EINVAL;
 
 	switch (req->type) {
+	case PKVM_HYP_REQ_HYP_ALLOC:
+		ret = pkvm_hyp_topup(PKVM_TOPUP_HYP_ALLOC, req->mem.nr_pages);
+		break;
 	}
 
 	trace_kvm_handle_pkvm_hyp_req(req, ret);
diff --git a/arch/arm64/kvm/trace_pkvm.h b/arch/arm64/kvm/trace_pkvm.h
index 3966c111e3ad..493225e3282d 100644
--- a/arch/arm64/kvm/trace_pkvm.h
+++ b/arch/arm64/kvm/trace_pkvm.h
@@ -9,9 +9,11 @@
 #define TRACE_SYSTEM kvm
 
 TRACE_DEFINE_ENUM(PKVM_HYP_NO_REQ);
+TRACE_DEFINE_ENUM(PKVM_HYP_REQ_HYP_ALLOC);
 
-#define PKVM_HYP_REQ_TYPES \
-	{ PKVM_HYP_NO_REQ, "NO_REQ" }
+#define PKVM_HYP_REQ_TYPES				\
+	{ PKVM_HYP_NO_REQ, "NO_REQ" },			\
+	{ PKVM_HYP_REQ_HYP_ALLOC, "HYP_ALLOC" }
 
 TRACE_EVENT(kvm_handle_pkvm_hyp_req,
 	TP_PROTO(struct pkvm_hyp_req *req, int ret),
-- 
2.55.0.508.g3f0d502094-goog