4.14-stable review patch. If anyone has any objections, please let me know.
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From: James Morse james.morse@arm.com
Commit c97e166e54b662717d20ec2e36761758d2b6a7c2 upstream.
Make tpidr_el2 a cpu-offset for per-cpu variables in the same way the host uses tpidr_el1. This lets tpidr_el{1,2} have the same value, and on VHE they can be the same register.
KVM calls hyp_panic() when anything unexpected happens. This may occur while a guest owns the EL1 registers. KVM stashes the vcpu pointer in tpidr_el2, which it uses to find the host context in order to restore the host EL1 registers before parachuting into the host's panic().
The host context is a struct kvm_cpu_context allocated in the per-cpu area, and mapped to hyp. Given the per-cpu offset for this CPU, this is easy to find. Change hyp_panic() to take a pointer to the struct kvm_cpu_context. Wrap these calls with an asm function that retrieves the struct kvm_cpu_context from the host's per-cpu area.
Copy the per-cpu offset from the hosts tpidr_el1 into tpidr_el2 during kvm init. (Later patches will make this unnecessary for VHE hosts)
We print out the vcpu pointer as part of the panic message. Add a back reference to the 'running vcpu' in the host cpu context to preserve this.
Signed-off-by: James Morse james.morse@arm.com Reviewed-by: Christoffer Dall cdall@linaro.org Signed-off-by: Catalin Marinas catalin.marinas@arm.com Signed-off-by: Marc Zyngier marc.zyngier@arm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/arm64/include/asm/kvm_host.h | 2 ++ arch/arm64/kvm/hyp/hyp-entry.S | 12 ++++++++++++ arch/arm64/kvm/hyp/s2-setup.c | 3 +++ arch/arm64/kvm/hyp/switch.c | 25 +++++++++++++------------ 4 files changed, 30 insertions(+), 12 deletions(-)
--- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -194,6 +194,8 @@ struct kvm_cpu_context { u64 sys_regs[NR_SYS_REGS]; u32 copro[NR_COPRO_REGS]; }; + + struct kvm_vcpu *__hyp_running_vcpu; };
typedef struct kvm_cpu_context kvm_cpu_context_t; --- a/arch/arm64/kvm/hyp/hyp-entry.S +++ b/arch/arm64/kvm/hyp/hyp-entry.S @@ -179,6 +179,18 @@ ENTRY(__hyp_do_panic) eret ENDPROC(__hyp_do_panic)
+ENTRY(__hyp_panic) + /* + * '=kvm_host_cpu_state' is a host VA from the constant pool, it may + * not be accessible by this address from EL2, hyp_panic() converts + * it with kern_hyp_va() before use. + */ + ldr x0, =kvm_host_cpu_state + mrs x1, tpidr_el2 + add x0, x0, x1 + b hyp_panic +ENDPROC(__hyp_panic) + .macro invalid_vector label, target = __hyp_panic .align 2 \label: --- a/arch/arm64/kvm/hyp/s2-setup.c +++ b/arch/arm64/kvm/hyp/s2-setup.c @@ -84,5 +84,8 @@ u32 __hyp_text __init_stage2_translation
write_sysreg(val, vtcr_el2);
+ /* copy tpidr_el1 into tpidr_el2 for use by HYP */ + write_sysreg(read_sysreg(tpidr_el1), tpidr_el2); + return parange; } --- a/arch/arm64/kvm/hyp/switch.c +++ b/arch/arm64/kvm/hyp/switch.c @@ -289,9 +289,9 @@ int __hyp_text __kvm_vcpu_run(struct kvm u64 exit_code;
vcpu = kern_hyp_va(vcpu); - write_sysreg(vcpu, tpidr_el2);
host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context); + host_ctxt->__hyp_running_vcpu = vcpu; guest_ctxt = &vcpu->arch.ctxt;
__sysreg_save_host_state(host_ctxt); @@ -406,7 +406,8 @@ again:
static const char __hyp_panic_string[] = "HYP panic:\nPS:%08llx PC:%016llx ESR:%08llx\nFAR:%016llx HPFAR:%016llx PAR:%016llx\nVCPU:%p\n";
-static void __hyp_text __hyp_call_panic_nvhe(u64 spsr, u64 elr, u64 par) +static void __hyp_text __hyp_call_panic_nvhe(u64 spsr, u64 elr, u64 par, + struct kvm_vcpu *vcpu) { unsigned long str_va;
@@ -420,35 +421,35 @@ static void __hyp_text __hyp_call_panic_ __hyp_do_panic(str_va, spsr, elr, read_sysreg(esr_el2), read_sysreg_el2(far), - read_sysreg(hpfar_el2), par, - (void *)read_sysreg(tpidr_el2)); + read_sysreg(hpfar_el2), par, vcpu); }
-static void __hyp_text __hyp_call_panic_vhe(u64 spsr, u64 elr, u64 par) +static void __hyp_text __hyp_call_panic_vhe(u64 spsr, u64 elr, u64 par, + struct kvm_vcpu *vcpu) { panic(__hyp_panic_string, spsr, elr, read_sysreg_el2(esr), read_sysreg_el2(far), - read_sysreg(hpfar_el2), par, - (void *)read_sysreg(tpidr_el2)); + read_sysreg(hpfar_el2), par, vcpu); }
static hyp_alternate_select(__hyp_call_panic, __hyp_call_panic_nvhe, __hyp_call_panic_vhe, ARM64_HAS_VIRT_HOST_EXTN);
-void __hyp_text __noreturn __hyp_panic(void) +void __hyp_text __noreturn hyp_panic(struct kvm_cpu_context *__host_ctxt) { + struct kvm_vcpu *vcpu = NULL; + u64 spsr = read_sysreg_el2(spsr); u64 elr = read_sysreg_el2(elr); u64 par = read_sysreg(par_el1);
if (read_sysreg(vttbr_el2)) { - struct kvm_vcpu *vcpu; struct kvm_cpu_context *host_ctxt;
- vcpu = (struct kvm_vcpu *)read_sysreg(tpidr_el2); - host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context); + host_ctxt = kern_hyp_va(__host_ctxt); + vcpu = host_ctxt->__hyp_running_vcpu; __timer_save_state(vcpu); __deactivate_traps(vcpu); __deactivate_vm(vcpu); @@ -456,7 +457,7 @@ void __hyp_text __noreturn __hyp_panic(v }
/* Call panic for real */ - __hyp_call_panic()(spsr, elr, par); + __hyp_call_panic()(spsr, elr, par, vcpu);
unreachable(); }