Hello Brijesh,
On Mon, Mar 30, 2020 at 11:00:14AM -0500, Brijesh Singh wrote:
>
> On 3/30/20 1:23 AM, Ashish Kalra wrote:
> > From: Ashish Kalra <ashish.kalra@xxxxxxx>
> >
> > Reset the host's page encryption bitmap related to kernel
> > specific page encryption status settings before we load a
> > new kernel by kexec. We cannot reset the complete
> > page encryption bitmap here as we need to retain the
> > UEFI/OVMF firmware specific settings.
> >
> > Signed-off-by: Ashish Kalra <ashish.kalra@xxxxxxx>
> > ---
> > arch/x86/kernel/kvm.c | 28 ++++++++++++++++++++++++++++
> > 1 file changed, 28 insertions(+)
> >
> > diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
> > index 8fcee0b45231..ba6cce3c84af 100644
> > --- a/arch/x86/kernel/kvm.c
> > +++ b/arch/x86/kernel/kvm.c
> > @@ -34,6 +34,7 @@
> > #include <asm/hypervisor.h>
> > #include <asm/tlb.h>
> > #include <asm/cpuidle_haltpoll.h>
> > +#include <asm/e820/api.h>
> >
> > static int kvmapf = 1;
> >
> > @@ -357,6 +358,33 @@ static void kvm_pv_guest_cpu_reboot(void *unused)
> > */
> > if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
> > wrmsrl(MSR_KVM_PV_EOI_EN, 0);
> > + /*
> > + * Reset the host's page encryption bitmap related to kernel
> > + * specific page encryption status settings before we load a
> > + * new kernel by kexec. NOTE: We cannot reset the complete
> > + * page encryption bitmap here as we need to retain the
> > + * UEFI/OVMF firmware specific settings.
> > + */
> > + if (kvm_para_has_feature(KVM_FEATURE_SEV_LIVE_MIGRATION) &&
> > + (smp_processor_id() == 0)) {
>
>
> In patch 13/14, the KVM_FEATURE_SEV_LIVE_MIGRATION is set
> unconditionally and because of that now the below code will be executed
> on non-SEV guest. IMO, this feature must be cleared for non-SEV guest to
> avoid making unnecessary hypercall's.
>
>
I will additionally add a sev_active() check here to ensure that we don't make the unnecassary hypercalls on non-SEV guests.
> > + unsigned long nr_pages;
> > + int i;
> > +
> > + for (i = 0; i < e820_table->nr_entries; i++) {
> > + struct e820_entry *entry = &e820_table->entries[i];
> > + unsigned long start_pfn, end_pfn;
> > +
> > + if (entry->type != E820_TYPE_RAM)
> > + continue;
> > +
> > + start_pfn = entry->addr >> PAGE_SHIFT;
> > + end_pfn = (entry->addr + entry->size) >> PAGE_SHIFT;
> > + nr_pages = DIV_ROUND_UP(entry->size, PAGE_SIZE);
> > +
> > + kvm_sev_hypercall3(KVM_HC_PAGE_ENC_STATUS,
> > + entry->addr, nr_pages, 1);
> > + }
> > + }
> > kvm_pv_disable_apf();
> > kvm_disable_steal_time();
> > }
Thanks,
Ashish
