From: Mathias Krause <minipli@xxxxxxxxxxxxxx> Enhance the CR0.WP toggling test to do additional tests via the emulator as forcing KVM to emulate page protections exercises different flows than shoving the correct bits into hardware, e.g. KVM has had at least one bug when CR0.WP is guest owned. Link: https://lore.kernel.org/kvm/ea3a8fbc-2bf8-7442-e498-3e5818384c83@xxxxxxxxxxxxxx Signed-off-by: Mathias Krause <minipli@xxxxxxxxxxxxxx> [sean: check AC_FEP_MASK instead of fep_available()] Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx> --- x86/access.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/x86/access.c b/x86/access.c index 4a3ca265..70d81bf0 100644 --- a/x86/access.c +++ b/x86/access.c @@ -1108,8 +1108,9 @@ static int do_cr0_wp_access(ac_test_t *at, int flags) set_efer_nx(0); if (!ac_test_do_access(at)) { - printf("%s: supervisor write with CR0.WP=%d did not %s\n", - __FUNCTION__, cr0_wp, cr0_wp ? "FAULT" : "SUCCEED"); + printf("%s: %ssupervisor write with CR0.WP=%d did not %s\n", + __FUNCTION__, (flags & AC_FEP_MASK) ? "emulated " : "", + cr0_wp, cr0_wp ? "FAULT" : "SUCCEED"); return 1; } @@ -1127,6 +1128,10 @@ static int check_toggle_cr0_wp(ac_pt_env_t *pt_env) err += do_cr0_wp_access(&at, 0); err += do_cr0_wp_access(&at, AC_CPU_CR0_WP_MASK); + if (!(invalid_mask & AC_FEP_MASK)) { + err += do_cr0_wp_access(&at, AC_FEP_MASK); + err += do_cr0_wp_access(&at, AC_FEP_MASK | AC_CPU_CR0_WP_MASK); + } return err == 0; } -- 2.40.0.348.gf938b09366-goog
