Shared memory containing steal time counter should be set to decrypted when guest memory is encrypted.
Co-developed-by: Bo Gan <[email protected]> Signed-off-by: Bo Gan <[email protected]> Signed-off-by: Alexey Makhalov <[email protected]> --- arch/x86/kernel/cpu/vmware.c | 41 ++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) diff --git a/arch/x86/kernel/cpu/vmware.c b/arch/x86/kernel/cpu/vmware.c index 8997295a5a5c..e33400d4f2c1 100644 --- a/arch/x86/kernel/cpu/vmware.c +++ b/arch/x86/kernel/cpu/vmware.c @@ -32,6 +32,7 @@ #include <linux/sched/cputime.h> #include <linux/kmsg_dump.h> #include <linux/panic_notifier.h> +#include <linux/set_memory.h> #include <asm/div64.h> #include <asm/x86_init.h> #include <asm/hypervisor.h> @@ -39,6 +40,7 @@ #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 @@ -379,9 +381,47 @@ static struct notifier_block vmware_pv_reboot_nb = { .notifier_call = vmware_pv_reboot_notify, }; +/* + * Map per-CPU variables for all possible CPUs as decrypted. + * Do this early in boot, before sharing the corresponding + * guest physical addresses with the hypervisor. + */ +static void __init set_shared_memory_decrypted(void) +{ + int cpu; + + if (!cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT)) + return; + + for_each_possible_cpu(cpu) { + unsigned long size = sizeof(vmw_steal_time); + unsigned long addr = (unsigned long)&per_cpu(vmw_steal_time, + cpu); + + /* + * There is no generic high-level API to mark memory as + * decrypted. Intel's set_memory_decrypted() depends on the + * buddy allocator and can fail early in boot if a page split + * is required and allocation is not possible. Use AMD's + * early_set_memory_decrypted() instead, which can perform + * the split during early boot. + */ + early_set_memory_decrypted(addr, size); + + /* That's it for AMD */ + if (cc_vendor == CC_VENDOR_AMD) + continue; + + set_memory_decrypted(addr & PAGE_MASK, 1UL << + get_order((addr & ~PAGE_MASK) + size)); + + } +} + #ifdef CONFIG_SMP static void __init vmware_smp_prepare_boot_cpu(void) { + set_shared_memory_decrypted(); vmware_guest_cpu_init(); native_smp_prepare_boot_cpu(); } @@ -444,6 +484,7 @@ 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 + set_shared_memory_decrypted(); vmware_guest_cpu_init(); #endif } -- 2.43.7
