Many selftests use GUEST_DONE() to signal the end of guest code, which
is handled in userspace. In most tests, the test exits and there is no
need to clean up the ucall_pool->in_use bitmap.
If there are many guest code functions using GUEST_DONE(), or of guest
code functions are run many times, the ucall_pool->in_use bitmap will
fill up, causing later runs of the same guest code function to fail.
This patch allows ucall_free() to be called from userspace on uc.hva,
which will unset and free the correct struct ucall in the pool,
allowing ucalls to continue being used.
Change-Id: I2cb2aeed4b291b1bfb2bece001d09c509cd10446
Signed-off-by: Ackerley Tng <ackerleytng@xxxxxxxxxx>
---
.../testing/selftests/kvm/include/ucall_common.h | 1 +
tools/testing/selftests/kvm/lib/ucall_common.c | 16 ++++++++--------
2 files changed, 9 insertions(+), 8 deletions(-)
diff --git a/tools/testing/selftests/kvm/include/ucall_common.h b/tools/testing/selftests/kvm/include/ucall_common.h
index d9d6581b8d4f..b6b850d0319a 100644
--- a/tools/testing/selftests/kvm/include/ucall_common.h
+++ b/tools/testing/selftests/kvm/include/ucall_common.h
@@ -40,6 +40,7 @@ __printf(5, 6) void ucall_assert(uint64_t cmd, const char *exp,
const char *fmt, ...);
uint64_t get_ucall(struct kvm_vcpu *vcpu, struct ucall *uc);
void ucall_init(struct kvm_vm *vm, vm_paddr_t mmio_gpa);
+void ucall_free(struct ucall *uc);
int ucall_nr_pages_required(uint64_t page_size);
/*
diff --git a/tools/testing/selftests/kvm/lib/ucall_common.c b/tools/testing/selftests/kvm/lib/ucall_common.c
index 42151e571953..9b6865c39ea7 100644
--- a/tools/testing/selftests/kvm/lib/ucall_common.c
+++ b/tools/testing/selftests/kvm/lib/ucall_common.c
@@ -21,24 +21,24 @@ int ucall_nr_pages_required(uint64_t page_size)
/*
* ucall_pool holds per-VM values (global data is duplicated by each VM), it
- * must not be accessed from host code.
+ * should generally not be accessed from host code other than via ucall_free(),
+ * to cleanup after using GUEST_DONE()
*/
static struct ucall_header *ucall_pool;
void ucall_init(struct kvm_vm *vm, vm_paddr_t mmio_gpa)
{
- struct ucall_header *hdr;
struct ucall *uc;
vm_vaddr_t vaddr;
int i;
- vaddr = vm_vaddr_alloc_shared(vm, sizeof(*hdr), KVM_UTIL_MIN_VADDR,
- MEM_REGION_DATA);
- hdr = (struct ucall_header *)addr_gva2hva(vm, vaddr);
- memset(hdr, 0, sizeof(*hdr));
+ vaddr = vm_vaddr_alloc_shared(vm, sizeof(*ucall_pool),
+ KVM_UTIL_MIN_VADDR, MEM_REGION_DATA);
+ ucall_pool = (struct ucall_header *)addr_gva2hva(vm, vaddr);
+ memset(ucall_pool, 0, sizeof(*ucall_pool));
for (i = 0; i < KVM_MAX_VCPUS; ++i) {
- uc = &hdr->ucalls[i];
+ uc = &ucall_pool->ucalls[i];
uc->hva = uc;
}
@@ -73,7 +73,7 @@ static struct ucall *ucall_alloc(void)
return NULL;
}
-static void ucall_free(struct ucall *uc)
+void ucall_free(struct ucall *uc)
{
/* Beware, here be pointer arithmetic. */
clear_bit(uc - ucall_pool->ucalls, ucall_pool->in_use);
--
2.49.0.1045.g170613ef41-goog
