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Merge branch kvm-arm64/pkvm-psci into kvmarm-master/next

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* kvm-arm64/pkvm-psci:
  : .
  : Cleanup of the pKVM PSCI relay CPU entry code, making it slightly
  : easier to follow, should someone have to wade into these waters
  : ever again.
  : .
  KVM: arm64: Remove extra ISBs when using msr_hcr_el2
  KVM: arm64: pkvm: Use direct function pointers for cpu_{on,resume}
  KVM: arm64: pkvm: Turn __kvm_hyp_init_cpu into an inner label
  KVM: arm64: pkvm: Simplify BTI handling on CPU boot
  KVM: arm64: pkvm: Move error handling to the end of kvm_hyp_cpu_entry

Signed-off-by: Marc Zyngier <maz@kernel.org>
This commit is contained in:
Marc Zyngier
2026-04-08 12:23:24 +01:00
parent e85d1c0cc7 54a3cc1454
commit b693940e81
7 changed files with 43 additions and 59 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
arch/arm64/include/asm/el2_setup.h
View File

@@ -50,7 +50,6 @@
* effectively VHE-only or not.
*/
msr_hcr_el2 x0 // Setup HCR_EL2 as nVHE
isb
mov x1, #1 // Write something to FAR_EL1
msr far_el1, x1
isb
@@ -64,7 +63,6 @@
.LnE2H0_\@:
orr x0, x0, #HCR_E2H
msr_hcr_el2 x0
isb
.LnVHE_\@:
.endm

3
arch/arm64/include/asm/kvm_asm.h
View File

@@ -301,7 +301,8 @@ 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,

6
arch/arm64/include/asm/sysreg.h
View File

@@ -1121,11 +1121,9 @@
.macro msr_hcr_el2, reg
#if IS_ENABLED(CONFIG_AMPERE_ERRATUM_AC04_CPU_23)
dsb nsh
msr hcr_el2, \reg
isb
#else
msr hcr_el2, \reg
#endif
msr hcr_el2, \reg
isb // Required by AMPERE_ERRATUM_AC04_CPU_23
.endm
#else

1
arch/arm64/kernel/hyp-stub.S
View File

@@ -103,7 +103,6 @@ SYM_CODE_START_LOCAL(__finalise_el2)
// Engage the VHE magic!
mov_q x0, HCR_HOST_VHE_FLAGS
msr_hcr_el2 x0
isb
// Use the EL1 allocated stack, per-cpu offset
mrs x0, sp_el1

11
arch/arm64/kvm/hyp/nvhe/host.S
View File

@@ -125,7 +125,6 @@ SYM_FUNC_START(__hyp_do_panic)
mrs x0, hcr_el2
bic x0, x0, #HCR_VM
msr_hcr_el2 x0
isb
tlbi vmalls12e1
dsb nsh
#endif
@@ -291,13 +290,3 @@ SYM_CODE_START(__kvm_hyp_host_forward_smc)
ret
SYM_CODE_END(__kvm_hyp_host_forward_smc)
/*
* kvm_host_psci_cpu_entry is called through br instruction, which requires
* bti j instruction as compilers (gcc and llvm) doesn't insert bti j for external
* functions, but bti c instead.
*/
SYM_CODE_START(kvm_host_psci_cpu_entry)
bti j
b __kvm_host_psci_cpu_entry
SYM_CODE_END(kvm_host_psci_cpu_entry)

41
arch/arm64/kvm/hyp/nvhe/hyp-init.S
View File

@@ -173,9 +173,8 @@ 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
SYM_CODE_END(kvm_hyp_cpu_entry)
/*
* PSCI CPU_SUSPEND / SYSTEM_SUSPEND entry point
@@ -183,32 +182,17 @@ SYM_CODE_END(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
b __kvm_hyp_init_cpu
SYM_CODE_END(kvm_hyp_cpu_resume)
ldr x29, =__kvm_host_psci_cpu_resume_entry
/*
* Common code for CPU entry points. Initializes EL2 state and
* installs the hypervisor before handing over to a C handler.
*
* x0: struct kvm_nvhe_init_params PA
* x1: bool is_cpu_on
*/
SYM_CODE_START_LOCAL(__kvm_hyp_init_cpu)
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
cmp x0, #CurrentEL_EL2
b.eq 2f
b.ne 1f
/* The core booted in EL1. KVM cannot be initialized on it. */
1: wfe
wfi
b 1b
2: msr SPsel, #1 // We want to use SP_EL{1,2}
msr SPsel, #1 // We want to use SP_EL2
init_el2_hcr 0
@@ -218,11 +202,16 @@ SYM_CODE_START_LOCAL(__kvm_hyp_init_cpu)
mov x0, x28
bl ___kvm_hyp_init // Clobbers x0..x2
/* Leave idmap. */
mov x0, x29
ldr x1, =kvm_host_psci_cpu_entry
br x1
SYM_CODE_END(__kvm_hyp_init_cpu)
/* Leave idmap -- using BLR is OK, LR is restored from host context */
blr x29
// The core booted in EL1, or the C code unexpectedly returned.
// Either way, KVM cannot be initialized on it.
1: wfe
wfi
b 1b
SYM_CODE_END(kvm_hyp_cpu_resume)
SYM_CODE_END(kvm_hyp_cpu_entry)
SYM_CODE_START(__kvm_handle_stub_hvc)
/*

38
arch/arm64/kvm/hyp/nvhe/psci-relay.c
View File

@@ -201,24 +201,14 @@ 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);
trace_hyp_enter(host_ctxt, HYP_REASON_PSCI);
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);
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);
@@ -227,6 +217,26 @@ 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(&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)
{
if (is_psci_0_1(cpu_off, func_id) || is_psci_0_1(migrate, func_id))