| Message ID | 697cbb9301acf18296b65bb63686b6c0d422e382.1588711355.git.ashish.kalra@amd.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add AMD SEV guest live migration support | expand |
On Tue, May 5, 2020 at 2:21 PM Ashish Kalra <Ashish.Kalra@amd.com> wrote: > > From: Ashish Kalra <ashish.kalra@amd.com> > > 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. > > The host's page encryption bitmap is maintained for the > guest to keep the encrypted/decrypted state of the guest pages, > therefore we need to explicitly mark all shared pages as > encrypted again before rebooting into the new guest kernel. > > Signed-off-by: Ashish Kalra <ashish.kalra@amd.com> > --- > 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 4b29815de873..a8bc30d5b15b 100644 > --- a/arch/x86/kernel/kvm.c > +++ b/arch/x86/kernel/kvm.c > @@ -35,6 +35,7 @@ > #include <asm/hypervisor.h> > #include <asm/tlb.h> > #include <asm/cpuidle_haltpoll.h> > +#include <asm/e820/api.h> > > static int kvmapf = 1; > > @@ -358,6 +359,33 @@ 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 (sev_live_migration_enabled() & (smp_processor_id() == 0)) { > + int i; > + unsigned long nr_pages; > + > + for (i = 0; i < e820_table->nr_entries; i++) { > + struct e820_entry *entry = &e820_table->entries[i]; > + unsigned long start_pfn; > + unsigned long end_pfn; > + > + if (entry->type != E820_TYPE_RAM) > + continue; What should the behavior be for other memory types that are not expected to be mucked with by firmware? Should we avoid resetting the enc status of pmem/pram pages? My intuition here is that we should only preserve the enc status of those bits that are set by the firmware. > + > + 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(); > } > -- > 2.17.1 >
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c index 4b29815de873..a8bc30d5b15b 100644 --- a/arch/x86/kernel/kvm.c +++ b/arch/x86/kernel/kvm.c @@ -35,6 +35,7 @@ #include <asm/hypervisor.h> #include <asm/tlb.h> #include <asm/cpuidle_haltpoll.h> +#include <asm/e820/api.h> static int kvmapf = 1; @@ -358,6 +359,33 @@ 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 (sev_live_migration_enabled() & (smp_processor_id() == 0)) { + int i; + unsigned long nr_pages; + + for (i = 0; i < e820_table->nr_entries; i++) { + struct e820_entry *entry = &e820_table->entries[i]; + unsigned long start_pfn; + unsigned long 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(); }