Re: [PATCH 09/10] rust/timer/hpet: add qom and qdev APIs support
> > > This needs to be "match addr & !4".
> >
> > I understand it's not necessary:
> >
> > In timer_and_addr(), I've masked the address with 0x18.
> >
> > fn timer_and_addr(&self, addr: hwaddr) ->
> > Option<(&BqlRefCell, hwaddr)> {
> > let timer_id: usize = ((addr - 0x100) / 0x20) as usize;
> >
> > if timer_id > self.num_timers.get() {
> > None
> > } else {
> > Some((&self.timers[timer_id], addr & 0x18))
> >
>
> Ah, this should be 0x1C (or perhaps 0x1F). Otherwise there is a bug in
> accessing the high 32 bits of a 64-bit register; shift will always be 0 in
> HPETTimer::read and write.
Yes, you're right. Then we should use 0x1F so that invalid access could
detected (or loged in future) and ignored.
Based on the similar reason, C side also need to use "addr & (0x1f | ~4)"
instead of 0x18 to catch invalid access. If I'm right, I can submit a
fix.
Thanks,
Zhao
Re: [PATCH 09/10] rust/timer/hpet: add qom and qdev APIs support
Il sab 8 feb 2025, 11:36 Zhao Liu ha scritto:
> On Wed, Jan 29, 2025 at 11:58:14AM +0100, Paolo Bonzini wrote:
> > Date: Wed, 29 Jan 2025 11:58:14 +0100
> > From: Paolo Bonzini
> > Subject: Re: [PATCH 09/10] rust/timer/hpet: add qom and qdev APIs support
> >
> >
> >
> > On Sat, Jan 25, 2025 at 1:32 PM Zhao Liu wrote:
> > > fn read(&mut self, addr: hwaddr, _size: u32) -> u64 {
> >
> > This can be &self.
>
> Done.
>
> > > let shift: u64 = (addr & 4) * 8;
> > >
> > > +match addr {
> > > +HPET_TN_CFG_REG => self.config >> shift, // including
> interrupt capabilities
> >
> > This needs to be "match addr & !4".
>
> I understand it's not necessary:
>
> In timer_and_addr(), I've masked the address with 0x18.
>
> fn timer_and_addr(&self, addr: hwaddr) ->
> Option<(&BqlRefCell, hwaddr)> {
> let timer_id: usize = ((addr - 0x100) / 0x20) as usize;
>
> if timer_id > self.num_timers.get() {
> None
> } else {
> Some((&self.timers[timer_id], addr & 0x18))
>
Ah, this should be 0x1C (or perhaps 0x1F). Otherwise there is a bug in
accessing the high 32 bits of a 64-bit register; shift will always be 0 in
HPETTimer::read and write.
// No need for HPETClass. Just like OBJECT_DECLARE_SIMPLE_TYPE in C.
>
> Then this can be "grep", as a reference.
>
Sure.
Thanks,
Paolo
> > type Class = ::Class;
> > const TYPE_NAME: &'static CStr = crate::TYPE_HPET;
> > }
> >
> > which is indeed more similar to OBJECT_DECLARE_SIMPLE_TYPE().
>
> Awesome! Thanks.
>
> Regards,
> Zhao
>
>
Re: [PATCH 09/10] rust/timer/hpet: add qom and qdev APIs support
On Wed, Jan 29, 2025 at 11:58:14AM +0100, Paolo Bonzini wrote:
> Date: Wed, 29 Jan 2025 11:58:14 +0100
> From: Paolo Bonzini
> Subject: Re: [PATCH 09/10] rust/timer/hpet: add qom and qdev APIs support
>
>
>
> On Sat, Jan 25, 2025 at 1:32 PM Zhao Liu wrote:
> > fn read(&mut self, addr: hwaddr, _size: u32) -> u64 {
>
> This can be &self.
Done.
> > let shift: u64 = (addr & 4) * 8;
> >
> > +match addr {
> > +HPET_TN_CFG_REG => self.config >> shift, // including
> > interrupt capabilities
>
> This needs to be "match addr & !4".
I understand it's not necessary:
In timer_and_addr(), I've masked the address with 0x18.
fn timer_and_addr(&self, addr: hwaddr) -> Option<(&BqlRefCell,
hwaddr)> {
let timer_id: usize = ((addr - 0x100) / 0x20) as usize;
if timer_id > self.num_timers.get() {
None
} else {
Some((&self.timers[timer_id], addr & 0x18))
}
}
And in HPETState::read(), I pass the masked address to
HPETTimer::read():
fn read(&self, addr: hwaddr, size: u32) -> u64 {
let shift: u64 = (addr & 4) * 8;
if (0x100..=0x3ff).contains(&addr) {
match self.timer_and_addr(addr) {
None => 0, // Reserved,
Some((timer, addr)) => timer.borrow_mut().read(addr, size),
}
}
Ah, the `addr` variable in Some() is misleading, and I should use
anothor name like `tn_addr`.
0x18 is a subset of !0x4, so the bitwise & operation with !0x4 can be
omitted (I understand that this is why you also omitted this in the C
side in the commit c2366567378dd :-) ).
But `match addr & !4` is also reasonable, which explicitly emphasize
`& !4` makes the code clearer. I would do this.
> > +HPET_TN_CMP_REG => self.cmp >> shift,// comparator register
> > +HPET_TN_FSB_ROUTE_REG => self.fsb >> shift,
> > +_ => {
> > +// TODO: Add trace point - trace_hpet_ram_read_invalid()
> > +// Reserved.
> > +0
> > +}
> > +}
> > +}
> > +
> > +fn write(&mut self, addr: hwaddr, value: u64, size: u32) {
> > +let shift = ((addr & 4) * 8) as u32;
> > +let len = std::cmp::min(size * 8, 64 - shift);
> > +
> > +match addr {
> > +HPET_TN_CFG_REG => self.set_tn_cfg_reg(shift, len, value),
>
> Likewise.
Done. Thanks!
> > +fn write(&self, addr: hwaddr, value: u64, size: u32) {
> > +let shift = ((addr & 4) * 8) as u32;
> > +let len = std::cmp::min(size * 8, 64 - shift);
> > +
> > +// TODO: Add trace point - trace_hpet_ram_write(addr, value)
> > +if (0x100..=0x3ff).contains(&addr
> ) {
> > +match self.timer_and_addr(addr) {
> > +None => return, // Reserved.
>
> Clippy complains about an unnecessary return, just replace it with "()".
Fixed.
> > +Some((timer, addr)) => timer.borrow_mut().write(addr,
> > value, size),
> > +}
>
> > +
> > +fn reset_hold(&self, _type: ResetType) {
> > +let sbd = self.upcast::();
> > +
> > +for timer in self.timers.iter().take(self.num_timers.get()) {
> > +timer.borrow_mut().reset();
> > +}
> > +
> > +self.counter.set(0);
> > +self.config.set(0);
> > +self.pit_enabled.set(true);
> > +self.hpet_offset.set(0);
> > +
> > +HPETFwConfig::update_hpet_cfg(
> > +self.hpet_id.get(),
> > +Some(self.capability.get() as u32),
> > +Some((*sbd).mmio[0].addr),
> > +);
>
> This can be simply sbd.mmio[0].addr, without the (*...).
>
> Also, you can change update_hpet_cfg to take arguments without the Option<>
> around them.
Good idea! Done.
> > +// TODO: add OBJECT_DECLARE_SIMPLE_TYPE.
> > +#[repr(C)]
> > +pub struct HPETClass {
> > +parent_class: ::Class,
> > +}
> > +
> > +unsafe impl ObjectType for HPETState {
> > +type Class = HPETClass;
> > +const TYPE_NAME: &'static CStr = crate::TYPE_HPET;
> > +}
>
> No need for HPETClass (and for ClassInitImpl), just do
>
> unsafe impl ObjectType for HPETState {
Pls let me add a comment here:
// No need for HPETClass. Just like OBJECT_DECLARE_SIMPLE_TYPE in C.
Then this can be "grep", as a reference.
> type Class = ::Class;
> const TYPE_NAME: &'static CStr = crate::TYPE_HPET;
> }
>
> which is indeed more similar to OBJECT_DECLARE_SIMPLE_TYPE().
Awesome! Thanks.
Regards,
Zhao
Re: [PATCH 09/10] rust/timer/hpet: add qom and qdev APIs support
On Sat, Jan 25, 2025 at 1:32 PM Zhao Liu wrote:
fn read(&mut self, addr: hwaddr, _size: u32) -> u64 {
This can be &self.
let shift: u64 = (addr & 4) * 8;
+match addr {
+HPET_TN_CFG_REG => self.config >> shift, // including interrupt
capabilities
This needs to be "match addr & !4".
+HPET_TN_CMP_REG => self.cmp >> shift,// comparator register
+HPET_TN_FSB_ROUTE_REG => self.fsb >> shift,
+_ => {
+// TODO: Add trace point - trace_hpet_ram_read_invalid()
+// Reserved.
+0
+}
+}
+}
+
+fn write(&mut self, addr: hwaddr, value: u64, size: u32) {
+let shift = ((addr & 4) * 8) as u32;
+let len = std::cmp::min(size * 8, 64 - shift);
+
+match addr {
+HPET_TN_CFG_REG => self.set_tn_cfg_reg(shift, len, value),
Likewise.
+fn write(&self, addr: hwaddr, value: u64, size: u32) {
+let shift = ((addr & 4) * 8) as u32;
+let len = std::cmp::min(size * 8, 64 - shift);
+
+// TODO: Add trace point - trace_hpet_ram_write(addr, value)
+if (0x100..=0x3ff).contains(&addr
) {
+match self.timer_and_addr(addr) {
+None => return, // Reserved.
Clippy complains about an unnecessary return, just replace it with "()".
+Some((timer, addr)) => timer.borrow_mut().write(addr, value,
size),
+}
+
+fn reset_hold(&self, _type: ResetType) {
+let sbd = self.upcast::();
+
+for timer in self.timers.iter().take(self.num_timers.get()) {
+timer.borrow_mut().reset();
+}
+
+self.counter.set(0);
+self.config.set(0);
+self.pit_enabled.set(true);
+self.hpet_offset.set(0);
+
+HPETFwConfig::update_hpet_cfg(
+self.hpet_id.get(),
+Some(self.capability.get() as u32),
+Some((*sbd).mmio[0].addr),
+);
This can be simply sbd.mmio[0].addr, without the (*...).
Also, you can change update_hpet_cfg to take arguments without the
Option<> around them.
+// TODO: add OBJECT_DECLARE_SIMPLE_TYPE.
+#[repr(C)]
+pub struct HPETClass {
+parent_class: ::Class,
+}
+
+unsafe impl ObjectType for HPETState {
+type Class = HPETClass;
+const TYPE_NAME: &'static CStr = crate::TYPE_HPET;
+}
No need for HPETClass (and for ClassInitImpl), just do
unsafe impl ObjectType for HPETState {
type Class = ::Class;
const TYPE_NAME: &'static CStr = crate::TYPE_HPET;
}
which is indeed more similar to OBJECT_DECLARE_SIMPLE_TYPE().
Paolo
