On Thu, Apr 15, 2021 at 04:01:16PM +0000, Ashish Kalra wrote: > From: Ashish Kalra <ashish.kalra@xxxxxxx> > > The guest support for detecting and enabling SEV Live migration > feature uses the following logic : > > - kvm_init_plaform() invokes check_kvm_sev_migration() which > checks if its booted under the EFI > > - If not EFI, > > i) check for the KVM_FEATURE_CPUID Where do you do that? $ git grep KVM_FEATURE_CPUID $ Do you mean kvm_para_has_feature(KVM_FEATURE_SEV_LIVE_MIGRATION) per chance? > diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c > index 78bb0fae3982..94ef16d263a7 100644 > --- a/arch/x86/kernel/kvm.c > +++ b/arch/x86/kernel/kvm.c > @@ -26,6 +26,7 @@ > #include <linux/kprobes.h> > #include <linux/nmi.h> > #include <linux/swait.h> > +#include <linux/efi.h> > #include <asm/timer.h> > #include <asm/cpu.h> > #include <asm/traps.h> > @@ -429,6 +430,59 @@ static inline void __set_percpu_decrypted(void *ptr, unsigned long size) > early_set_memory_decrypted((unsigned long) ptr, size); > } > > +static int __init setup_kvm_sev_migration(void) kvm_init_sev_migration() or so. ... > @@ -48,6 +50,8 @@ EXPORT_SYMBOL_GPL(sev_enable_key); > > bool sev_enabled __section(".data"); > > +bool sev_live_migration_enabled __section(".data"); Pls add a function called something like: bool sev_feature_enabled(enum sev_feature) and gets SEV_FEATURE_LIVE_MIGRATION and then use it instead of adding yet another boolean which contains whether some aspect of SEV has been enabled or not. Then add a static enum sev_feature sev_features; in mem_encrypt.c and that function above will query that sev_features enum for set flags. Then, if you feel bored, you could convert sme_active, sev_active, sev_es_active, mem_encrypt_active and whetever else code needs to query any aspect of SEV being enabled or not, to that function. > +void __init check_kvm_sev_migration(void) > +{ > + if (sev_active() && > + kvm_para_has_feature(KVM_FEATURE_SEV_LIVE_MIGRATION)) { Save an indentation level: if (!sev_active() || !kvm_para_has_feature(KVM_FEATURE_SEV_LIVE_MIGRATION)) return; > + unsigned long nr_pages; > + int i; > + > + pr_info("KVM enable live migration\n"); That should be at the end of the function and say: pr_info("KVM live migration enabled.\n"); > + WRITE_ONCE(sev_live_migration_enabled, true); Why WRITE_ONCE? And that needs to go to the end of the function too. Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette