On Tue, Aug 13, 2024 at 09:21:12AM +0200, Janosch Frank wrote:
On 8/7/24 5:45 PM, Christoph Schlameuss wrote:
Add a test case verifying basic running and interaction of ucontrol VMs. Fill the segment and page tables for allocated memory and map memory on first access.
- uc_map_unmap Store and load data to mapped and unmapped memory and use pic segment translation handling to map memory on access.
Signed-off-by: Christoph Schlameuss schlameuss@linux.ibm.com
.../selftests/kvm/s390x/ucontrol_test.c | 167 +++++++++++++++++- 1 file changed, 166 insertions(+), 1 deletion(-)
[...]
+static void init_st_pt(FIXTURE_DATA(uc_kvm) * self) +{
- struct kvm_sync_regs *sync_regs = &self->run->s.regs;
- u64 first_pt_addr, ste, s_addr, pte;
- struct kvm_run *run = self->run;
- void *se_addr;
- int si, pi;
- u64 *phd;
- /* set PASCE addr */
- self->pgd = self->base_gpa + SZ_1M;
- phd = gpa2hva(self, self->pgd);
- memset(phd, 0xff, VM_MEM_TABLE_SIZE);
- first_pt_addr = self->pgd + (VM_MEM_TABLE_SIZE * VM_MEM_MAX_M);
- /* for each segment in the VM */
- for (si = 0; si < VM_MEM_MAX_M; si++) {
/* build segment table entry (ste) */ste = (first_pt_addr + (VM_MEM_TABLE_SIZE * si)) & ~0x7fful;/* store ste in st */phd[si] = ste;se_addr = gpa2hva(self, phd[si]);s_addr = self->base_gpa + (si * SZ_1M);memset(se_addr, 0xff, VM_MEM_TABLE_SIZE);/* for each page in the segment (VM) */for (pi = 0; pi < (SZ_1M / PAGE_SIZE); pi++) {/* build page table entry (pte) */pte = (s_addr + (pi * PAGE_SIZE)) & ~0xffful;/* store pte in pt */((u64 *)se_addr)[pi] = pte;}- }
- pr_debug("segment table entry %p (0x%lx) --> %p\n",
phd, phd[0], gpa2hva(self, (phd[0] & ~0x7fful)));- print_hex_bytes("st", (u64)phd, 64);
- print_hex_bytes("pt", (u64)gpa2hva(self, phd[0]), 128);
- /* PASCE TT=00 for segment table */
- sync_regs->crs[1] = self->pgd | 0x3;
- run->kvm_dirty_regs |= KVM_SYNC_CRS;
+}
Having a closer look at this I don't understand why we need to setup DAT in the guest. Also, the guest's memory easily fits in a couple of segment entries so you could set the table length TL in the ASCE to one page instead of 4.
I did only create the tables to be able to switch the DAT on and with that use a PSW that is a bit more normal. Switching the DAT off will work fine for the tests here without loosing any coverage in KVM. So I will remove it here and in the skey test.