Re: [RFC 13/16] x86/kvmclock: Share hvclock memory with the host

Vitaly Kuznetsov
2020-05-25T15:22:19Z

"Kirill A. Shutemov" <kirill@shutemov.name> writes:

> hvclock is shared between the guest and the hypervisor. It has to be
> accessible by host.
>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> ---
> arch/x86/kernel/kvmclock.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
> index 34b18f6eeb2c..ac6c2abe0d0f 100644
> --- a/arch/x86/kernel/kvmclock.c
> +++ b/arch/x86/kernel/kvmclock.c
> @@ -253,7 +253,7 @@ static void __init kvmclock_init_mem(void)
> * hvclock is shared between the guest and the hypervisor, must
> * be mapped decrypted.
> */
> - if (sev_active()) {
> + if (sev_active() || kvm_mem_protected()) {
> r = set_memory_decrypted((unsigned long) hvclock_mem,
> 1UL << order);
> if (r) {

Sorry if I missed something but we have other structures which KVM guest
share with the host,

sev_map_percpu_data():
...
for_each_possible_cpu(cpu) {
__set_percpu_decrypted(&per_cpu(apf_reason, cpu), sizeof(apf_reason));
__set_percpu_decrypted(&per_cpu(steal_time, cpu), sizeof(steal_time));
__set_percpu_decrypted(&per_cpu(kvm_apic_eoi, cpu), sizeof(kvm_apic_eoi));
}
...

Do you handle them somehow in the patchset? (I'm probably just blind
failing to see how 'early_set_memory_decrypted()' is wired up)

--
Vitaly