Commit 59c6e12d authored by Marc Zyngier's avatar Marc Zyngier
Browse files

KVM: arm64: pkvm: Use direct function pointers for cpu_{on,resume} 



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.

Reviewed-by: default avatarFuad Tabba <tabba@google.com>
Tested-by: default avatarFuad Tabba <tabba@google.com>
Link: https://patch.msgid.link/20260321212419.2803972-5-maz@kernel.org


Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
parent ba64e273

arch/arm64/include/asm/kvm_asm.h

+2 −1
Original line number Diff line number Diff line
@@ -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,

arch/arm64/kvm/hyp/nvhe/hyp-init.S

+3 −6
Original line number Diff line number Diff line
@@ -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.

arch/arm64/kvm/hyp/nvhe/psci-relay.c

+24 −15
Original line number Diff line number Diff line
@@ -200,28 +200,37 @@ 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;

	struct kvm_cpu_context *host_ctxt = host_data_ptr(host_ctxt);



	host_ctxt = host_data_ptr(host_ctxt);

	cpu_reg(host_ctxt, 0) = r0;

	write_sysreg_el2(pc, SYS_ELR);



	if (is_cpu_on)

		boot_args = this_cpu_ptr(&cpu_on_args);

	else

		boot_args = this_cpu_ptr(&suspend_args);

	write_sysreg_el1(INIT_SCTLR_EL1_MMU_OFF, SYS_SCTLR);

	write_sysreg(INIT_PSTATE_EL1, SPSR_EL2);



	cpu_reg(host_ctxt, 0) = boot_args->r0;

	write_sysreg_el2(boot_args->pc, SYS_ELR);

	__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);



	if (is_cpu_on)

	release_boot_args(boot_args);



	write_sysreg_el1(INIT_SCTLR_EL1_MMU_OFF, SYS_SCTLR);

	write_sysreg(INIT_PSTATE_EL1, SPSR_EL2);

	__kvm_host_psci_cpu_entry(pc, r0);

}



	__host_enter(host_ctxt);

asmlinkage void __noreturn __kvm_host_psci_cpu_resume_entry(void)

{

	struct psci_boot_args *boot_args = this_cpu_ptr(&suspend_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)