From: Thomas Huth <thuth@xxxxxxxxxx> We recently discovered a bug with the time management in nested scenarios which got fixed by kernel commit "KVM: s390: vsie: Fix the initialization of the epoch extension (epdx) field". This adds a simple test for this bug so that it is easier to determine whether the host kernel of a machine has already been fixed or not. Signed-off-by: Thomas Huth <thuth@xxxxxxxxxx> Reviewed-by: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20221208170502.17984-1-thuth@xxxxxxxxxx Signed-off-by: Nico Boehr <nrb@xxxxxxxxxxxxx> --- s390x/sie.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) diff --git a/s390x/sie.c b/s390x/sie.c index 87575b2..cd3cea1 100644 --- a/s390x/sie.c +++ b/s390x/sie.c @@ -58,6 +58,33 @@ static void test_diags(void) } } +static void test_epoch_ext(void) +{ + u32 instr[] = { + 0xb2780000, /* STCKE 0 */ + 0x83000044 /* DIAG 0x44 to intercept */ + }; + + if (!test_facility(139)) { + report_skip("epdx: Multiple Epoch Facility is not available"); + return; + } + + guest[0] = 0x00; + memcpy(guest_instr, instr, sizeof(instr)); + + vm.sblk->gpsw.addr = PAGE_SIZE * 2; + vm.sblk->gpsw.mask = PSW_MASK_64; + + vm.sblk->ecd |= ECD_MEF; + vm.sblk->epdx = 0x47; /* Setting the epoch extension here ... */ + + sie(&vm); + + /* ... should result in the same epoch extension here: */ + report(guest[0] == 0x47, "epdx: different epoch is visible in the guest"); +} + static void setup_guest(void) { setup_vm(); @@ -80,6 +107,7 @@ int main(void) setup_guest(); test_diags(); + test_epoch_ext(); sie_guest_destroy(&vm); done: -- 2.39.2
