[V3 06/11] KVM: selftests: Consolidate common code for popuplating

From: Peter Gonda
Date: Wed Aug 10 2022 - 11:21:21 EST


From: Sean Christopherson <seanjc@xxxxxxxxxx>

Make ucall() a common helper that populates struct ucall, and only calls
into arch code to make the actually call out to userspace.

Rename all arch-specific helpers to make it clear they're arch-specific,
and to avoid collisions with common helpers (one more on its way...)

Add WRITE_ONCE() to stores in ucall() code to as already done to aarch64
code in commit 9e2f6498efbb ("selftests: KVM: Handle compiler
optimizations in ucall") to prevent clang optimizations breaking ucalls.

Cc: Colton Lewis <coltonlewis@xxxxxxxxxx>
Cc: Andrew Jones <drjones@xxxxxxxxxx>
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
Signed-off-by: Peter Gonda <pgonda@xxxxxxxxxx>
---
tools/testing/selftests/kvm/Makefile | 1 +
.../selftests/kvm/include/ucall_common.h | 23 ++++++++++++++++---
.../testing/selftests/kvm/lib/aarch64/ucall.c | 20 ++++------------
tools/testing/selftests/kvm/lib/riscv/ucall.c | 23 ++++---------------
tools/testing/selftests/kvm/lib/s390x/ucall.c | 23 ++++---------------
.../testing/selftests/kvm/lib/ucall_common.c | 20 ++++++++++++++++
.../testing/selftests/kvm/lib/x86_64/ucall.c | 23 ++++---------------
7 files changed, 60 insertions(+), 73 deletions(-)
create mode 100644 tools/testing/selftests/kvm/lib/ucall_common.c

diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index 690b499c3471..39fc5e8e5594 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -46,6 +46,7 @@ LIBKVM += lib/perf_test_util.c
LIBKVM += lib/rbtree.c
LIBKVM += lib/sparsebit.c
LIBKVM += lib/test_util.c
+LIBKVM += lib/ucall_common.c

LIBKVM_x86_64 += lib/x86_64/apic.c
LIBKVM_x86_64 += lib/x86_64/handlers.S
diff --git a/tools/testing/selftests/kvm/include/ucall_common.h b/tools/testing/selftests/kvm/include/ucall_common.h
index ee79d180e07e..5a85f5318bbe 100644
--- a/tools/testing/selftests/kvm/include/ucall_common.h
+++ b/tools/testing/selftests/kvm/include/ucall_common.h
@@ -24,10 +24,27 @@ struct ucall {
uint64_t args[UCALL_MAX_ARGS];
};

-void ucall_init(struct kvm_vm *vm, void *arg);
-void ucall_uninit(struct kvm_vm *vm);
+void ucall_arch_init(struct kvm_vm *vm, void *arg);
+void ucall_arch_uninit(struct kvm_vm *vm);
+void ucall_arch_do_ucall(vm_vaddr_t uc);
+uint64_t ucall_arch_get_ucall(struct kvm_vcpu *vcpu, struct ucall *uc);
+
void ucall(uint64_t cmd, int nargs, ...);
-uint64_t get_ucall(struct kvm_vcpu *vcpu, struct ucall *uc);
+
+static inline void ucall_init(struct kvm_vm *vm, void *arg)
+{
+ ucall_arch_init(vm, arg);
+}
+
+static inline void ucall_uninit(struct kvm_vm *vm)
+{
+ ucall_arch_uninit(vm);
+}
+
+static inline uint64_t get_ucall(struct kvm_vcpu *vcpu, struct ucall *uc)
+{
+ return ucall_arch_get_ucall(vcpu, uc);
+}

#define GUEST_SYNC_ARGS(stage, arg1, arg2, arg3, arg4) \
ucall(UCALL_SYNC, 6, "hello", stage, arg1, arg2, arg3, arg4)
diff --git a/tools/testing/selftests/kvm/lib/aarch64/ucall.c b/tools/testing/selftests/kvm/lib/aarch64/ucall.c
index ed237b744690..1c81a6a5c1f2 100644
--- a/tools/testing/selftests/kvm/lib/aarch64/ucall.c
+++ b/tools/testing/selftests/kvm/lib/aarch64/ucall.c
@@ -21,7 +21,7 @@ static bool ucall_mmio_init(struct kvm_vm *vm, vm_paddr_t gpa)
return true;
}

-void ucall_init(struct kvm_vm *vm, void *arg)
+void ucall_arch_init(struct kvm_vm *vm, void *arg)
{
vm_paddr_t gpa, start, end, step, offset;
unsigned int bits;
@@ -64,30 +64,18 @@ void ucall_init(struct kvm_vm *vm, void *arg)
TEST_FAIL("Can't find a ucall mmio address");
}

-void ucall_uninit(struct kvm_vm *vm)
+void ucall_arch_uninit(struct kvm_vm *vm)
{
ucall_exit_mmio_addr = 0;
sync_global_to_guest(vm, ucall_exit_mmio_addr);
}

-void ucall(uint64_t cmd, int nargs, ...)
+void ucall_arch_do_ucall(vm_vaddr_t uc)
{
- struct ucall uc = {};
- va_list va;
- int i;
-
- WRITE_ONCE(uc.cmd, cmd);
- nargs = min(nargs, UCALL_MAX_ARGS);
-
- va_start(va, nargs);
- for (i = 0; i < nargs; ++i)
- WRITE_ONCE(uc.args[i], va_arg(va, uint64_t));
- va_end(va);
-
WRITE_ONCE(*ucall_exit_mmio_addr, (vm_vaddr_t)&uc);
}

-uint64_t get_ucall(struct kvm_vcpu *vcpu, struct ucall *uc)
+uint64_t ucall_arch_get_ucall(struct kvm_vcpu *vcpu, struct ucall *uc)
{
struct kvm_run *run = vcpu->run;
struct ucall ucall = {};
diff --git a/tools/testing/selftests/kvm/lib/riscv/ucall.c b/tools/testing/selftests/kvm/lib/riscv/ucall.c
index 087b9740bc8f..b1598f418c1f 100644
--- a/tools/testing/selftests/kvm/lib/riscv/ucall.c
+++ b/tools/testing/selftests/kvm/lib/riscv/ucall.c
@@ -10,11 +10,11 @@
#include "kvm_util.h"
#include "processor.h"

-void ucall_init(struct kvm_vm *vm, void *arg)
+void ucall_arch_init(struct kvm_vm *vm, void *arg)
{
}

-void ucall_uninit(struct kvm_vm *vm)
+void ucall_arch_uninit(struct kvm_vm *vm)
{
}

@@ -44,27 +44,14 @@ struct sbiret sbi_ecall(int ext, int fid, unsigned long arg0,
return ret;
}

-void ucall(uint64_t cmd, int nargs, ...)
+void ucall_arch_do_ucall(vm_vaddr_t uc)
{
- struct ucall uc = {
- .cmd = cmd,
- };
- va_list va;
- int i;
-
- nargs = min(nargs, UCALL_MAX_ARGS);
-
- va_start(va, nargs);
- for (i = 0; i < nargs; ++i)
- uc.args[i] = va_arg(va, uint64_t);
- va_end(va);
-
sbi_ecall(KVM_RISCV_SELFTESTS_SBI_EXT,
KVM_RISCV_SELFTESTS_SBI_UCALL,
- (vm_vaddr_t)&uc, 0, 0, 0, 0, 0);
+ uc, 0, 0, 0, 0, 0);
}

-uint64_t get_ucall(struct kvm_vcpu *vcpu, struct ucall *uc)
+uint64_t ucall_arch_get_ucall(struct kvm_vcpu *vcpu, struct ucall *uc)
{
struct kvm_run *run = vcpu->run;
struct ucall ucall = {};
diff --git a/tools/testing/selftests/kvm/lib/s390x/ucall.c b/tools/testing/selftests/kvm/lib/s390x/ucall.c
index 73dc4e21190f..114cb4af295f 100644
--- a/tools/testing/selftests/kvm/lib/s390x/ucall.c
+++ b/tools/testing/selftests/kvm/lib/s390x/ucall.c
@@ -6,34 +6,21 @@
*/
#include "kvm_util.h"

-void ucall_init(struct kvm_vm *vm, void *arg)
+void ucall_arch_init(struct kvm_vm *vm, void *arg)
{
}

-void ucall_uninit(struct kvm_vm *vm)
+void ucall_arch_uninit(struct kvm_vm *vm)
{
}

-void ucall(uint64_t cmd, int nargs, ...)
+void ucall_arch_do_ucall(vm_vaddr_t uc)
{
- struct ucall uc = {
- .cmd = cmd,
- };
- va_list va;
- int i;
-
- nargs = min(nargs, UCALL_MAX_ARGS);
-
- va_start(va, nargs);
- for (i = 0; i < nargs; ++i)
- uc.args[i] = va_arg(va, uint64_t);
- va_end(va);
-
/* Exit via DIAGNOSE 0x501 (normally used for breakpoints) */
- asm volatile ("diag 0,%0,0x501" : : "a"(&uc) : "memory");
+ asm volatile ("diag 0,%0,0x501" : : "a"(uc) : "memory");
}

-uint64_t get_ucall(struct kvm_vcpu *vcpu, struct ucall *uc)
+uint64_t ucall_arch_get_ucall(struct kvm_vcpu *vcpu, struct ucall *uc)
{
struct kvm_run *run = vcpu->run;
struct ucall ucall = {};
diff --git a/tools/testing/selftests/kvm/lib/ucall_common.c b/tools/testing/selftests/kvm/lib/ucall_common.c
new file mode 100644
index 000000000000..2395c7f1d543
--- /dev/null
+++ b/tools/testing/selftests/kvm/lib/ucall_common.c
@@ -0,0 +1,20 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include "kvm_util.h"
+
+void ucall(uint64_t cmd, int nargs, ...)
+{
+ struct ucall uc = {};
+ va_list va;
+ int i;
+
+ WRITE_ONCE(uc.cmd, cmd);
+
+ nargs = min(nargs, UCALL_MAX_ARGS);
+
+ va_start(va, nargs);
+ for (i = 0; i < nargs; ++i)
+ WRITE_ONCE(uc.args[i], va_arg(va, uint64_t));
+ va_end(va);
+
+ ucall_arch_do_ucall((vm_vaddr_t)&uc);
+}
diff --git a/tools/testing/selftests/kvm/lib/x86_64/ucall.c b/tools/testing/selftests/kvm/lib/x86_64/ucall.c
index e5f0f9e0d3ee..9f532dba1003 100644
--- a/tools/testing/selftests/kvm/lib/x86_64/ucall.c
+++ b/tools/testing/selftests/kvm/lib/x86_64/ucall.c
@@ -8,34 +8,21 @@

#define UCALL_PIO_PORT ((uint16_t)0x1000)

-void ucall_init(struct kvm_vm *vm, void *arg)
+void ucall_arch_init(struct kvm_vm *vm, void *arg)
{
}

-void ucall_uninit(struct kvm_vm *vm)
+void ucall_arch_uninit(struct kvm_vm *vm)
{
}

-void ucall(uint64_t cmd, int nargs, ...)
+void ucall_arch_do_ucall(vm_vaddr_t uc)
{
- struct ucall uc = {
- .cmd = cmd,
- };
- va_list va;
- int i;
-
- nargs = min(nargs, UCALL_MAX_ARGS);
-
- va_start(va, nargs);
- for (i = 0; i < nargs; ++i)
- uc.args[i] = va_arg(va, uint64_t);
- va_end(va);
-
asm volatile("in %[port], %%al"
- : : [port] "d" (UCALL_PIO_PORT), "D" (&uc) : "rax", "memory");
+ : : [port] "d" (UCALL_PIO_PORT), "D" (uc) : "rax", "memory");
}

-uint64_t get_ucall(struct kvm_vcpu *vcpu, struct ucall *uc)
+uint64_t ucall_arch_get_ucall(struct kvm_vcpu *vcpu, struct ucall *uc)
{
struct kvm_run *run = vcpu->run;
struct ucall ucall = {};
--
2.37.1.559.g78731f0fdb-goog