On 15.07.2013, at 17:05, Bhushan Bharat-R65777 wrote: > > >> -----Original Message----- >> From: Alexander Graf [mailto:agraf@xxxxxxx] >> Sent: Monday, July 15, 2013 5:20 PM >> To: Bhushan Bharat-R65777 >> Cc: kvm@xxxxxxxxxxxxxxx; kvm-ppc@xxxxxxxxxxxxxxx; Wood Scott-B07421; Yoder >> Stuart-B08248; Bhushan Bharat-R65777 >> Subject: Re: [PATCH 5/5] powerpc: using reset hcall when kvm,has-reset >> >> >> On 15.07.2013, at 13:11, Bharat Bhushan wrote: >> >>> Detect the availability of the reset hcalls by looking at >>> kvm,has-reset property on the /hypervisor node in the device tree >>> passed to the VM and patches the reset mechanism to use reset hcall. >>> >>> This patch uses the reser hcall when kvm,has-reset is there in >> >> Your patch description is pretty broken :). >> >>> >>> Signed-off-by: Bharat Bhushan <bharat.bhushan@xxxxxxxxxxxxx> >>> --- >>> arch/powerpc/kernel/epapr_paravirt.c | 12 ++++++++++++ >>> 1 files changed, 12 insertions(+), 0 deletions(-) >>> >>> diff --git a/arch/powerpc/kernel/epapr_paravirt.c >>> b/arch/powerpc/kernel/epapr_paravirt.c >>> index d44a571..651d701 100644 >>> --- a/arch/powerpc/kernel/epapr_paravirt.c >>> +++ b/arch/powerpc/kernel/epapr_paravirt.c >>> @@ -22,6 +22,8 @@ >>> #include <asm/cacheflush.h> >>> #include <asm/code-patching.h> >>> #include <asm/machdep.h> >>> +#include <asm/kvm_para.h> >>> +#include <asm/kvm_host.h> >> >> Why would we need kvm_host.h? This is guest code. >> >>> >>> #if !defined(CONFIG_64BIT) || defined(CONFIG_PPC_BOOK3E_64) extern >>> void epapr_ev_idle(void); @@ -30,6 +32,14 @@ extern u32 >>> epapr_ev_idle_start[]; >>> >>> bool epapr_paravirt_enabled; >>> >>> +void epapr_hypercall_reset(char *cmd) { >>> + long ret; >>> + ret = kvm_hypercall0(KVM_HC_VM_RESET); >> >> Is this available without CONFIG_KVM_GUEST? kvm_hypercall() simply returns >> "unimplemented" for everything when that config option is not set. > > We are here because we patched the ppc_md.restart to point to new handler. > So I think we should patch the ppc_md.restart only if CONFIG_KVM_GUEST is true. We should only patch it if kvm_para_available(). That should guard us against everything. > > >> >>> + printk("error: system reset returned with error %ld\n", ret); >> >> So we should fall back to the normal reset handler here. > > Do you mean return normally from here, no BUG() etc? If we guard the patching against everything, we can treat a broken hcall as BUG. However, if we don't we want to fall back to the normal guts based reset. Alex -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
