On 3/29/20 11:23 PM, 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.
Can the commit message mention why host page encryption needs to be
reset ? Since the theme of these patches is guest migration in-SEV
context, it might be useful to mention why the host context comes in here.
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)) {
+ 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();
}
