linux-kernel - [RFC PATCH 19/34] gunyah: Add hypercalls for running a vCPU

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <20250424141341.841734-20-karim.manaouil@linaro.org>
Date: Thu, 24 Apr 2025 15:13:26 +0100
From: Karim Manaouil <karim.manaouil@...aro.org>
To: linux-kernel@...r.kernel.org,
	kvm@...r.kernel.org,
	linux-arm-msm@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	kvmarm@...ts.linux.dev
Cc: Karim Manaouil <karim.manaouil@...aro.org>,
	Alexander Graf <graf@...zon.com>,
	Alex Elder <elder@...nel.org>,
	Catalin Marinas <catalin.marinas@....com>,
	Fuad Tabba <tabba@...gle.com>,
	Joey Gouly <joey.gouly@....com>,
	Jonathan Corbet <corbet@....net>,
	Marc Zyngier <maz@...nel.org>,
	Mark Brown <broonie@...nel.org>,
	Mark Rutland <mark.rutland@....com>,
	Oliver Upton <oliver.upton@...ux.dev>,
	Paolo Bonzini <pbonzini@...hat.com>,
	Prakruthi Deepak Heragu <quic_pheragu@...cinc.com>,
	Quentin Perret <qperret@...gle.com>,
	Rob Herring <robh@...nel.org>,
	Srinivas Kandagatla <srini@...nel.org>,
	Srivatsa Vaddagiri <quic_svaddagi@...cinc.com>,
	Will Deacon <will@...nel.org>,
	Haripranesh S <haripran@....qualcomm.com>,
	Carl van Schaik <cvanscha@....qualcomm.com>,
	Murali Nalajala <mnalajal@...cinc.com>,
	Sreenivasulu Chalamcharla <sreeniva@....qualcomm.com>,
	Trilok Soni <tsoni@...cinc.com>,
	Stefan Schmidt <stefan.schmidt@...aro.org>,
	Elliot Berman <quic_eberman@...cinc.com>
Subject: [RFC PATCH 19/34] gunyah: Add hypercalls for running a vCPU

From: Elliot Berman <quic_eberman@...cinc.com>

Add hypercall to donate CPU time to a vCPU.

Signed-off-by: Elliot Berman <quic_eberman@...cinc.com>
Reviewed-by: Srivatsa Vaddagiri <quic_svaddagi@...cinc.com>
Signed-off-by: Karim Manaouil <karim.manaouil@...aro.org>
---
 arch/arm64/gunyah/gunyah_hypercall.c | 37 ++++++++++++++++++++++++++++
 include/linux/gunyah.h               | 35 ++++++++++++++++++++++++++
 2 files changed, 72 insertions(+)

diff --git a/arch/arm64/gunyah/gunyah_hypercall.c b/arch/arm64/gunyah/gunyah_hypercall.c
index 1302e128be6e..fee21df42c17 100644
--- a/arch/arm64/gunyah/gunyah_hypercall.c
+++ b/arch/arm64/gunyah/gunyah_hypercall.c
@@ -39,6 +39,7 @@ EXPORT_SYMBOL_GPL(arch_is_gunyah_guest);
 #define GUNYAH_HYPERCALL_HYP_IDENTIFY		GUNYAH_HYPERCALL(0x8000)
 #define GUNYAH_HYPERCALL_MSGQ_SEND		GUNYAH_HYPERCALL(0x801B)
 #define GUNYAH_HYPERCALL_MSGQ_RECV		GUNYAH_HYPERCALL(0x801C)
+#define GUNYAH_HYPERCALL_VCPU_RUN		GUNYAH_HYPERCALL(0x8065)
 /* clang-format on */
 
 /**
@@ -113,5 +114,41 @@ enum gunyah_error gunyah_hypercall_msgq_recv(u64 capid, void *buff, size_t size,
 }
 EXPORT_SYMBOL_GPL(gunyah_hypercall_msgq_recv);
 
+/**
+ * gunyah_hypercall_vcpu_run() - Donate CPU time to a vcpu
+ * @capid: capability ID of the vCPU to run
+ * @resume_data: Array of 3 state-specific resume data
+ * @resp: Filled reason why vCPU exited when return value is GUNYAH_ERROR_OK
+ *
+ * See also:
+ * https://github.com/quic/gunyah-hypervisor/blob/develop/docs/api/gunyah_api.md#run-a-proxy-scheduled-vcpu-thread
+ */
+enum gunyah_error
+gunyah_hypercall_vcpu_run(u64 capid, unsigned long *resume_data,
+			  struct gunyah_hypercall_vcpu_run_resp *resp)
+{
+	struct arm_smccc_1_2_regs args = {
+		.a0 = GUNYAH_HYPERCALL_VCPU_RUN,
+		.a1 = capid,
+		.a2 = resume_data[0],
+		.a3 = resume_data[1],
+		.a4 = resume_data[2],
+		/* C language says this will be implictly zero. Gunyah requires 0, so be explicit */
+		.a5 = 0,
+	};
+	struct arm_smccc_1_2_regs res;
+
+	arm_smccc_1_2_hvc(&args, &res);
+	if (res.a0 == GUNYAH_ERROR_OK) {
+		resp->sized_state = res.a1;
+		resp->state_data[0] = res.a2;
+		resp->state_data[1] = res.a3;
+		resp->state_data[2] = res.a4;
+	}
+
+	return res.a0;
+}
+EXPORT_SYMBOL_GPL(gunyah_hypercall_vcpu_run);
+
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("Gunyah Hypervisor Hypercalls");
diff --git a/include/linux/gunyah.h b/include/linux/gunyah.h
index 573e3bbd4cb6..f86f14018734 100644
--- a/include/linux/gunyah.h
+++ b/include/linux/gunyah.h
@@ -219,4 +219,39 @@ enum gunyah_error gunyah_hypercall_msgq_send(u64 capid, size_t size, void *buff,
 enum gunyah_error gunyah_hypercall_msgq_recv(u64 capid, void *buff, size_t size,
 					     size_t *recv_size, bool *ready);
 
+struct gunyah_hypercall_vcpu_run_resp {
+	union {
+		enum {
+			/* clang-format off */
+			/* VCPU is ready to run */
+			GUNYAH_VCPU_STATE_READY			= 0,
+			/* VCPU is sleeping until an interrupt arrives */
+			GUNYAH_VCPU_STATE_EXPECTS_WAKEUP	= 1,
+			/* VCPU is powered off */
+			GUNYAH_VCPU_STATE_POWERED_OFF		= 2,
+			/* VCPU is blocked in EL2 for unspecified reason */
+			GUNYAH_VCPU_STATE_BLOCKED		= 3,
+			/* VCPU has returned for MMIO READ */
+			GUNYAH_VCPU_ADDRSPACE_VMMIO_READ	= 4,
+			/* VCPU has returned for MMIO WRITE */
+			GUNYAH_VCPU_ADDRSPACE_VMMIO_WRITE	= 5,
+			/* VCPU blocked on fault where we can demand page */
+			GUNYAH_VCPU_ADDRSPACE_PAGE_FAULT	= 7,
+			/* clang-format on */
+		} state;
+		u64 sized_state;
+	};
+	u64 state_data[3];
+};
+
+enum {
+	GUNYAH_ADDRSPACE_VMMIO_ACTION_EMULATE = 0,
+	GUNYAH_ADDRSPACE_VMMIO_ACTION_RETRY = 1,
+	GUNYAH_ADDRSPACE_VMMIO_ACTION_FAULT = 2,
+};
+
+enum gunyah_error
+gunyah_hypercall_vcpu_run(u64 capid, unsigned long *resume_data,
+			  struct gunyah_hypercall_vcpu_run_resp *resp);
+
 #endif
-- 
2.39.5