On 03.03.21 14:09, David Hildenbrand wrote:
legacy_s390_alloc() was required for dealing with the absence of the ESOP
feature -- on old HW (< gen 10) and old z/VM versions (< 6.3).
As z/VM v6.2 (and even v6.3) is no longer supported since 2017 [1]
and we don't expect to have real users on such old hardware, let's drop
legacy_s390_alloc().
Still check+report an error just in case someone still runs on
such old z/VM environments, or someone runs under weird nested KVM
setups (where we can manually disable ESOP via the CPU model).
No need to check for KVM_CAP_GMAP - that should always be around on
kernels that also have KVM_CAP_DEVICE_CTRL (>= v3.15).
[1] https://www.ibm.com/support/lifecycle/search?q=z%2FVM
Suggested-by: Cornelia Huck <cohuck@xxxxxxxxxx>
Suggested-by: Thomas Huth <thuth@xxxxxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Richard Henderson <rth@xxxxxxxxxxx>
Cc: Halil Pasic <pasic@xxxxxxxxxxxxx>
Cc: Cornelia Huck <cohuck@xxxxxxxxxx>
Cc: Christian Borntraeger <borntraeger@xxxxxxxxxx>
Cc: Thomas Huth <thuth@xxxxxxxxxx>
Cc: Igor Mammedov <imammedo@xxxxxxxxxx>
Cc: Peter Xu <peterx@xxxxxxxxxx>
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
I agree, this should now be a corner case that we do not necessarily have to care about.
---
target/s390x/kvm.c | 43 +++++--------------------------------------
1 file changed, 5 insertions(+), 38 deletions(-)
diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c
index 7a892d663d..84b40572f2 100644
--- a/target/s390x/kvm.c
+++ b/target/s390x/kvm.c
@@ -161,8 +161,6 @@ static int cap_protected;
static int active_cmma;
-static void *legacy_s390_alloc(size_t size, uint64_t *align, bool shared);
-
static int kvm_s390_query_mem_limit(uint64_t *memory_limit)
{
struct kvm_device_attr attr = {
@@ -349,6 +347,11 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
"please use kernel 3.15 or newer");
return -1;
}
+ if (!kvm_check_extension(s, KVM_CAP_S390_COW)) {
+ error_report("KVM is missing capability KVM_CAP_S390_COW - "
+ "unsupported environment");
+ return -1;
+ }
cap_sync_regs = kvm_check_extension(s, KVM_CAP_SYNC_REGS);
cap_async_pf = kvm_check_extension(s, KVM_CAP_ASYNC_PF);
@@ -357,11 +360,6 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
cap_vcpu_resets = kvm_check_extension(s, KVM_CAP_S390_VCPU_RESETS);
cap_protected = kvm_check_extension(s, KVM_CAP_S390_PROTECTED);
- if (!kvm_check_extension(s, KVM_CAP_S390_GMAP)
- || !kvm_check_extension(s, KVM_CAP_S390_COW)) {
- phys_mem_set_alloc(legacy_s390_alloc);
- }
-
kvm_vm_enable_cap(s, KVM_CAP_S390_USER_SIGP, 0);
kvm_vm_enable_cap(s, KVM_CAP_S390_VECTOR_REGISTERS, 0);
kvm_vm_enable_cap(s, KVM_CAP_S390_USER_STSI, 0);
@@ -889,37 +887,6 @@ int kvm_s390_mem_op_pv(S390CPU *cpu, uint64_t offset, void *hostbuf,
return ret;
}
-/*
- * Legacy layout for s390:
- * Older S390 KVM requires the topmost vma of the RAM to be
- * smaller than an system defined value, which is at least 256GB.
- * Larger systems have larger values. We put the guest between
- * the end of data segment (system break) and this value. We
- * use 32GB as a base to have enough room for the system break
- * to grow. We also have to use MAP parameters that avoid
- * read-only mapping of guest pages.
- */
-static void *legacy_s390_alloc(size_t size, uint64_t *align, bool shared)
-{
- static void *mem;
-
- if (mem) {
- /* we only support one allocation, which is enough for initial ram */
- return NULL;
- }
-
- mem = mmap((void *) 0x800000000ULL, size,
- PROT_EXEC|PROT_READ|PROT_WRITE,
- MAP_SHARED | MAP_ANONYMOUS | MAP_FIXED, -1, 0);
- if (mem == MAP_FAILED) {
- mem = NULL;
- }
- if (mem && align) {
- *align = QEMU_VMALLOC_ALIGN;
- }
- return mem;
-}
-
static uint8_t const *sw_bp_inst;
static uint8_t sw_bp_ilen;
