[PATCH v2 2/2] x86/vmware: Fix steal time clock under SEV

[Alexey Makhalov]

Shared memory containing steal time counter should be set to
decrypted when SEV is active.

Co-developed-by: Bo Gan <bo....@broadcom.com>
Signed-off-by: Bo Gan <bo....@broadcom.com>
Signed-off-by: Alexey Makhalov <alexey.makha...@broadcom.com>
---
 arch/x86/kernel/cpu/vmware.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/arch/x86/kernel/cpu/vmware.c b/arch/x86/kernel/cpu/vmware.c
index 9883766715fe..b4e57d6ec2f5 100644
--- a/arch/x86/kernel/cpu/vmware.c
+++ b/arch/x86/kernel/cpu/vmware.c
@@ -36,6 +36,7 @@
 #include <asm/apic.h>
 #include <asm/vmware.h>
 #include <asm/svm.h>
+#include <asm/coco.h>
 
 #undef pr_fmt
 #define pr_fmt(fmt)    "vmware: " fmt
@@ -306,9 +307,30 @@ static struct notifier_block vmware_pv_reboot_nb = {
        .notifier_call = vmware_pv_reboot_notify,
 };
 
+static void __init sev_map_percpu_data(void)
+{
+       int cpu;
+
+       if (cc_vendor != CC_VENDOR_AMD ||
+           !cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT))
+               return;
+
+       for_each_possible_cpu(cpu) {
+               early_set_memory_decrypted(
+                       (unsigned long)&per_cpu(vmw_steal_time, cpu),
+                       sizeof(vmw_steal_time));
+       }
+}
+
 #ifdef CONFIG_SMP
 static void __init vmware_smp_prepare_boot_cpu(void)
 {
+       /*
+        * Map the per-cpu variables as decrypted before vmware_guest_cpu_init()
+        * shares the guest physical address with the hypervisor.
+        */
+       sev_map_percpu_data();
+
        vmware_guest_cpu_init();
        native_smp_prepare_boot_cpu();
 }
@@ -371,6 +393,7 @@ static void __init vmware_paravirt_ops_setup(void)
                                              vmware_cpu_down_prepare) < 0)
                        pr_err("vmware_guest: Failed to install cpu hotplug 
callbacks\n");
 #else
+               sev_map_percpu_data();
                vmware_guest_cpu_init();
 #endif
        }
-- 
2.39.4