Hi Michal,
On 20/04/2021 08:08, Michal Orzel wrote:
AArch64 system registers are 64bit whereas AArch32 ones
are 32bit or 64bit. MSR/MRS are expecting 64bit values thus
we should get rid of helpers READ/WRITE_SYSREG32
in favour of using READ/WRITE_SYSREG.
We should also use register_t type when reading sysregs
which can correspond to uint64_t or uint32_t.
Even though many AArch64 sysregs have upper 32bit reserved
it does not mean that they can't be widen in the future.
As a general comment, all your commit message contains information about
the goal (which is great). But they don't go much in details about the
actual changes. I have tried to point out where I think those details
would be helpful.
As there are no other places in the code using READ/WRITE_SYSREG32,
remove the helper macros.
Signed-off-by: Michal Orzel <[email protected]>
---
xen/arch/arm/vcpreg.c | 16 ++++++++++++++++
xen/include/asm-arm/arm64/sysregs.h | 5 -----
2 files changed, 16 insertions(+), 5 deletions(-)
diff --git a/xen/arch/arm/vcpreg.c b/xen/arch/arm/vcpreg.c
index c7f516ee0a..6cb7f3108c 100644
--- a/xen/arch/arm/vcpreg.c
+++ b/xen/arch/arm/vcpreg.c
@@ -48,6 +48,7 @@
*/
/* The name is passed from the upper macro to workaround macro expansion. */
+#ifdef CONFIG_ARM_32
#define TVM_REG(sz, func, reg...) \
static bool func(struct cpu_user_regs *regs, uint##sz##_t *r, bool read) \
{ \
@@ -61,6 +62,21 @@ static bool func(struct cpu_user_regs *regs, uint##sz##_t
*r, bool read) \
\
return true; \
}
+#else /* CONFIG_ARM_64 */
+#define TVM_REG(sz, func, reg...) \
+static bool func(struct cpu_user_regs *regs, uint##sz##_t *r, bool read) \
+{ \
+ struct vcpu *v = current; \
+ bool cache_enabled = vcpu_has_cache_enabled(v); \
+ \
+ GUEST_BUG_ON(read); \
+ WRITE_SYSREG(*r, reg); \
+ \
+ p2m_toggle_cache(v, cache_enabled); \
+ \
+ return true; \
+}
+#endif
It would be nice if this change can be explained in the commit message.
However, I think we can avoid the duplication by aliasing TVM_REG32() to
TVM_REG64() on Arm64.
#define TVM_REG32(regname, xreg) TVM_REG(32, vreg_emulate_##regname, xreg)
#define TVM_REG64(regname, xreg) TVM_REG(64, vreg_emulate_##regname, xreg)
diff --git a/xen/include/asm-arm/arm64/sysregs.h
b/xen/include/asm-arm/arm64/sysregs.h
index 077fd95fb7..83a1157ac4 100644
--- a/xen/include/asm-arm/arm64/sysregs.h
+++ b/xen/include/asm-arm/arm64/sysregs.h
@@ -86,11 +86,6 @@
#endif
/* Access to system registers */
-
-#define READ_SYSREG32(name) ((uint32_t)READ_SYSREG64(name))
-
-#define WRITE_SYSREG32(v, name) WRITE_SYSREG64((uint64_t)v, name)
-
#define WRITE_SYSREG64(v, name) do { \
uint64_t _r = v; \
asm volatile("msr "__stringify(name)", %0" : : "r" (_r)); \
Cheers,
--
Julien Grall
