From: Marc Zyngier <maz@kernel.org>
To: kvmarm@lists.linux.dev, kvm@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Cc: Joey Gouly <joey.gouly@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Oliver Upton <oupton@kernel.org>,
Zenghui Yu <yuzenghui@huawei.com>, Fuad Tabba <tabba@google.com>,
Will Deacon <will@kernel.org>,
Mostafa Saleh <smostafa@google.com>,
Quentin Perret <qperret@google.com>
Subject: [PATCH 4/5] KVM: arm64: pkvm: Use direct function pointers for cpu_{on,resume}
Date: Sat, 21 Mar 2026 21:24:18 +0000 [thread overview]
Message-ID: <20260321212419.2803972-5-maz@kernel.org> (raw)
In-Reply-To: <20260321212419.2803972-1-maz@kernel.org>
Instead of using a boolean to decide whether a CPU is booting or
resuming, just pass an actual function pointer around.
This makes the code a bit more straightforward to understand.
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
arch/arm64/include/asm/kvm_asm.h | 3 ++-
arch/arm64/kvm/hyp/nvhe/hyp-init.S | 9 +++----
arch/arm64/kvm/hyp/nvhe/psci-relay.c | 39 +++++++++++++++++-----------
3 files changed, 29 insertions(+), 22 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
index a1ad12c72ebf1..f4c769857fdfc 100644
--- a/arch/arm64/include/asm/kvm_asm.h
+++ b/arch/arm64/include/asm/kvm_asm.h
@@ -291,7 +291,8 @@ asmlinkage void __noreturn hyp_panic_bad_stack(void);
asmlinkage void kvm_unexpected_el2_exception(void);
struct kvm_cpu_context;
void handle_trap(struct kvm_cpu_context *host_ctxt);
-asmlinkage void __noreturn __kvm_host_psci_cpu_entry(bool is_cpu_on);
+asmlinkage void __noreturn __kvm_host_psci_cpu_on_entry(void);
+asmlinkage void __noreturn __kvm_host_psci_cpu_resume_entry(void);
void __noreturn __pkvm_init_finalise(void);
void kvm_nvhe_prepare_backtrace(unsigned long fp, unsigned long pc);
void kvm_patch_vector_branch(struct alt_instr *alt,
diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-init.S b/arch/arm64/kvm/hyp/nvhe/hyp-init.S
index 2e80fcbff2dff..64296b31da73d 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp-init.S
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-init.S
@@ -173,7 +173,7 @@ SYM_CODE_END(___kvm_hyp_init)
* x0: struct kvm_nvhe_init_params PA
*/
SYM_CODE_START(kvm_hyp_cpu_entry)
- mov x1, #1 // is_cpu_on = true
+ ldr x29, =__kvm_host_psci_cpu_on_entry
b __kvm_hyp_init_cpu
/*
@@ -182,11 +182,10 @@ SYM_CODE_START(kvm_hyp_cpu_entry)
* x0: struct kvm_nvhe_init_params PA
*/
SYM_CODE_START(kvm_hyp_cpu_resume)
- mov x1, #0 // is_cpu_on = false
+ ldr x29, =__kvm_host_psci_cpu_resume_entry
SYM_INNER_LABEL(__kvm_hyp_init_cpu, SYM_L_LOCAL)
mov x28, x0 // Stash arguments
- mov x29, x1
/* Check that the core was booted in EL2. */
mrs x0, CurrentEL
@@ -204,9 +203,7 @@ SYM_INNER_LABEL(__kvm_hyp_init_cpu, SYM_L_LOCAL)
bl ___kvm_hyp_init // Clobbers x0..x2
/* Leave idmap -- using BLR is OK, LR is restored from host context */
- mov x0, x29
- ldr x1, =__kvm_host_psci_cpu_entry
- blr x1
+ blr x29
// The core booted in EL1, or the C code unexpectedly returned.
// Either way, KVM cannot be initialized on it.
diff --git a/arch/arm64/kvm/hyp/nvhe/psci-relay.c b/arch/arm64/kvm/hyp/nvhe/psci-relay.c
index c3e196fb8b18f..cc698ceee9c8c 100644
--- a/arch/arm64/kvm/hyp/nvhe/psci-relay.c
+++ b/arch/arm64/kvm/hyp/nvhe/psci-relay.c
@@ -200,23 +200,12 @@ static int psci_system_suspend(u64 func_id, struct kvm_cpu_context *host_ctxt)
__hyp_pa(init_params), 0);
}
-asmlinkage void __noreturn __kvm_host_psci_cpu_entry(bool is_cpu_on)
+static void __noreturn __kvm_host_psci_cpu_entry(unsigned long pc, unsigned long r0)
{
- struct psci_boot_args *boot_args;
- struct kvm_cpu_context *host_ctxt;
-
- host_ctxt = host_data_ptr(host_ctxt);
-
- if (is_cpu_on)
- boot_args = this_cpu_ptr(&cpu_on_args);
- else
- boot_args = this_cpu_ptr(&suspend_args);
-
- cpu_reg(host_ctxt, 0) = boot_args->r0;
- write_sysreg_el2(boot_args->pc, SYS_ELR);
+ struct kvm_cpu_context *host_ctxt = host_data_ptr(host_ctxt);
- if (is_cpu_on)
- release_boot_args(boot_args);
+ cpu_reg(host_ctxt, 0) = r0;
+ write_sysreg_el2(pc, SYS_ELR);
write_sysreg_el1(INIT_SCTLR_EL1_MMU_OFF, SYS_SCTLR);
write_sysreg(INIT_PSTATE_EL1, SPSR_EL2);
@@ -224,6 +213,26 @@ asmlinkage void __noreturn __kvm_host_psci_cpu_entry(bool is_cpu_on)
__host_enter(host_ctxt);
}
+asmlinkage void __noreturn __kvm_host_psci_cpu_on_entry(void)
+{
+ struct psci_boot_args *boot_args = this_cpu_ptr(&cpu_on_args);
+ unsigned long pc, r0;
+
+ pc = READ_ONCE(boot_args->pc);
+ r0 = READ_ONCE(boot_args->r0);
+
+ release_boot_args(boot_args);
+
+ __kvm_host_psci_cpu_entry(pc, r0);
+}
+
+asmlinkage void __noreturn __kvm_host_psci_cpu_resume_entry(void)
+{
+ struct psci_boot_args *boot_args = this_cpu_ptr(&cpu_on_args);
+
+ __kvm_host_psci_cpu_entry(boot_args->pc, boot_args->r0);
+}
+
static unsigned long psci_0_1_handler(u64 func_id, struct kvm_cpu_context *host_ctxt)
{
if (is_psci_0_1(cpu_off, func_id) || is_psci_0_1(migrate, func_id))
--
2.47.3
next prev parent reply other threads:[~2026-03-21 21:24 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-21 21:24 [PATCH 0/5] KVM: arm64: pkvm; Rework aspects of the PSCI relay Marc Zyngier
2026-03-21 21:24 ` [PATCH 1/5] KVM: arm64: pkvm: Move error handling to the end of kvm_hyp_cpu_entry Marc Zyngier
2026-03-22 15:08 ` Fuad Tabba
2026-03-21 21:24 ` [PATCH 2/5] KVM: arm64: pkvm: Simplify BTI handling on CPU boot Marc Zyngier
2026-03-22 15:37 ` Fuad Tabba
2026-03-21 21:24 ` [PATCH 3/5] KVM: arm64: pkvm: Turn __kvm_hyp_init_cpu into an inner label Marc Zyngier
2026-03-22 15:43 ` Fuad Tabba
2026-03-21 21:24 ` Marc Zyngier [this message]
2026-03-22 15:49 ` [PATCH 4/5] KVM: arm64: pkvm: Use direct function pointers for cpu_{on,resume} Fuad Tabba
2026-03-23 8:43 ` Marc Zyngier
2026-03-21 21:24 ` [PATCH 5/5] KVM: arm64: Remove extra ISBs when using msr_hcr_el2 Marc Zyngier
2026-03-22 15:55 ` Fuad Tabba
2026-03-22 15:57 ` [PATCH 0/5] KVM: arm64: pkvm; Rework aspects of the PSCI relay Fuad Tabba
2026-03-23 11:05 ` Marc Zyngier
2026-03-23 12:33 ` Mostafa Saleh
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