From: Andre Przywara <andre.przywara@arm.com>
To: Alexandru Elisei <alexandru.elisei@arm.com>
Cc: kvm@vger.kernel.org, Marc Zyngier <maz@kernel.org>,
Julien Thierry <julien.thierry.kdev@gmail.com>,
Will Deacon <will@kernel.org>,
kvmarm@lists.cs.columbia.edu,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH kvmtool 21/21] hw/rtc: ARM/arm64: Use MMIO at higher addresses
Date: Thu, 18 Feb 2021 16:41:17 +0000 [thread overview]
Message-ID: <20210218164117.15fbd67a@slackpad.fritz.box> (raw)
In-Reply-To: <102807a0-812f-d4bf-b8b4-560f999c6e6c@arm.com>
On Thu, 18 Feb 2021 13:33:15 +0000
Alexandru Elisei <alexandru.elisei@arm.com> wrote:
> Hi Andre,
>
> On 12/10/20 2:29 PM, Andre Przywara wrote:
> > Using the RTC device at its legacy I/O address as set by IBM in 1981
> > was a kludge we used for simplicity on ARM platforms as well.
> > However this imposes problems due to their missing alignment and overlap
> > with the PCI I/O address space.
> >
> > Now that we can switch a device easily between using ioports and
> > MMIO, let's move the RTC out of the first 4K of memory on ARM platforms.
> >
> > That should be transparent for well behaved guests, since the change is
> > naturally reflected in the device tree.
> >
> > Signed-off-by: Andre Przywara <andre.przywara@arm.com>
> > ---
> > hw/rtc.c | 24 ++++++++++++++++--------
> > 1 file changed, 16 insertions(+), 8 deletions(-)
> >
> > diff --git a/hw/rtc.c b/hw/rtc.c
> > index ee4c9102..bdb88f0f 100644
> > --- a/hw/rtc.c
> > +++ b/hw/rtc.c
> > @@ -5,6 +5,15 @@
> >
> > #include <time.h>
> >
> > +#if defined(CONFIG_ARM) || defined(CONFIG_ARM64)
> > +#define RTC_BUS_TYPE DEVICE_BUS_MMIO
> > +#define RTC_BASE_ADDRESS 0x1010000
>
> This looks correct, the base address is the serial base address + 64k, so they
> don't overlap, and it doesn't overlap with the flash memory either. Same comment
> as for the serial, I think the reason for choosing this address should be
> mentioned, and the region should be put in the arch memory layout file. Other than
> that, the patch looks good.
Yep, will do!
Thanks,
Andre
>
> > +#else
> > +/* PORT 0070-007F - CMOS RAM/RTC (REAL TIME CLOCK) */
> > +#define RTC_BUS_TYPE DEVICE_BUS_IOPORT
> > +#define RTC_BASE_ADDRESS 0x70
> > +#endif
> > +
> > /*
> > * MC146818 RTC registers
> > */
> > @@ -49,7 +58,7 @@ static void cmos_ram_io(struct kvm_cpu *vcpu, u64 addr, u8 *data,
> > time_t ti;
> >
> > if (is_write) {
> > - if (addr == 0x70) { /* index register */
> > + if (addr == RTC_BASE_ADDRESS) { /* index register */
> > u8 value = ioport__read8(data);
> >
> > vcpu->kvm->nmi_disabled = value & (1UL << 7);
> > @@ -70,7 +79,7 @@ static void cmos_ram_io(struct kvm_cpu *vcpu, u64 addr, u8 *data,
> > return;
> > }
> >
> > - if (addr == 0x70)
> > + if (addr == RTC_BASE_ADDRESS) /* index register is write-only */
> > return;
> >
> > time(&ti);
> > @@ -127,7 +136,7 @@ static void generate_rtc_fdt_node(void *fdt,
> > u8 irq,
> > enum irq_type))
> > {
> > - u64 reg_prop[2] = { cpu_to_fdt64(0x70), cpu_to_fdt64(2) };
> > + u64 reg_prop[2] = { cpu_to_fdt64(RTC_BASE_ADDRESS), cpu_to_fdt64(2) };
> >
> > _FDT(fdt_begin_node(fdt, "rtc"));
> > _FDT(fdt_property_string(fdt, "compatible", "motorola,mc146818"));
> > @@ -139,7 +148,7 @@ static void generate_rtc_fdt_node(void *fdt,
> > #endif
> >
> > struct device_header rtc_dev_hdr = {
> > - .bus_type = DEVICE_BUS_IOPORT,
> > + .bus_type = RTC_BUS_TYPE,
> > .data = generate_rtc_fdt_node,
> > };
> >
> > @@ -151,8 +160,8 @@ int rtc__init(struct kvm *kvm)
> > if (r < 0)
> > return r;
> >
> > - /* PORT 0070-007F - CMOS RAM/RTC (REAL TIME CLOCK) */
> > - r = kvm__register_pio(kvm, 0x0070, 2, cmos_ram_io, NULL);
> > + r = kvm__register_iotrap(kvm, RTC_BASE_ADDRESS, 2, cmos_ram_io, NULL,
> > + RTC_BUS_TYPE);
> > if (r < 0)
> > goto out_device;
> >
> > @@ -170,8 +179,7 @@ dev_init(rtc__init);
> >
> > int rtc__exit(struct kvm *kvm)
> > {
> > - /* PORT 0070-007F - CMOS RAM/RTC (REAL TIME CLOCK) */
> > - kvm__deregister_pio(kvm, 0x0070);
> > + kvm__deregister_iotrap(kvm, RTC_BASE_ADDRESS, RTC_BUS_TYPE);
> >
> > return 0;
> > }
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next prev parent reply other threads:[~2021-02-18 16:43 UTC|newest]
Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-10 14:28 [PATCH kvmtool 00/21] Unify I/O port and MMIO trap handling Andre Przywara
2020-12-10 14:28 ` [PATCH kvmtool 01/21] ioport: Remove ioport__setup_arch() Andre Przywara
2021-02-10 17:44 ` Alexandru Elisei
2021-02-11 17:16 ` Andre Przywara
2021-02-11 17:32 ` Alexandru Elisei
2021-02-17 16:46 ` Andre Przywara
2021-02-22 10:23 ` Andre Przywara
2021-02-22 15:01 ` Alexandru Elisei
2020-12-10 14:28 ` [PATCH kvmtool 02/21] hw/serial: Use device abstraction for FDT generator function Andre Przywara
2021-02-11 12:05 ` Alexandru Elisei
2021-02-11 17:45 ` Andre Przywara
2020-12-10 14:28 ` [PATCH kvmtool 03/21] ioport: Retire .generate_fdt_node functionality Andre Przywara
2021-02-11 14:05 ` Alexandru Elisei
2021-02-17 15:54 ` Andre Przywara
2021-02-17 16:06 ` Alexandru Elisei
2020-12-10 14:28 ` [PATCH kvmtool 04/21] mmio: Extend handling to include ioport emulation Andre Przywara
2021-02-11 16:10 ` Alexandru Elisei
2021-02-17 17:43 ` Andre Przywara
2021-02-22 15:50 ` Alexandru Elisei
2020-12-10 14:28 ` [PATCH kvmtool 05/21] hw/i8042: Clean up data types Andre Przywara
2021-02-11 16:55 ` Alexandru Elisei
2021-02-17 17:46 ` Andre Przywara
2020-12-10 14:28 ` [PATCH kvmtool 06/21] hw/i8042: Refactor trap handler Andre Przywara
2021-02-11 17:23 ` Alexandru Elisei
2021-02-18 10:34 ` Andre Przywara
2021-02-18 11:17 ` Alexandru Elisei
2021-02-18 11:48 ` Andre Przywara
2021-02-22 16:03 ` Alexandru Elisei
2020-12-10 14:28 ` [PATCH kvmtool 07/21] hw/i8042: Switch to new trap handlers Andre Przywara
2021-02-12 10:41 ` Alexandru Elisei
2021-02-18 12:09 ` Andre Przywara
2021-02-22 16:19 ` Alexandru Elisei
2020-12-10 14:28 ` [PATCH kvmtool 08/21] x86/ioport: Refactor " Andre Przywara
2021-02-12 11:14 ` Alexandru Elisei
2020-12-10 14:28 ` [PATCH kvmtool 09/21] x86/ioport: Switch to new " Andre Przywara
2021-02-12 11:27 ` Alexandru Elisei
2021-02-18 14:05 ` Andre Przywara
2020-12-10 14:28 ` [PATCH kvmtool 10/21] hw/rtc: Refactor " Andre Przywara
2021-02-12 11:56 ` Alexandru Elisei
2020-12-10 14:28 ` [PATCH kvmtool 11/21] hw/rtc: Switch to new trap handler Andre Przywara
2021-02-12 12:02 ` Alexandru Elisei
2020-12-10 14:28 ` [PATCH kvmtool 12/21] hw/vesa: Switch trap handling to use MMIO handler Andre Przywara
2021-02-12 17:50 ` Alexandru Elisei
2020-12-10 14:29 ` [PATCH kvmtool 13/21] hw/serial: Refactor trap handler Andre Przywara
2021-02-16 14:22 ` Alexandru Elisei
2021-02-18 14:41 ` Andre Przywara
2021-02-22 17:40 ` Alexandru Elisei
2021-02-24 14:54 ` Andre Przywara
2020-12-10 14:29 ` [PATCH kvmtool 14/21] hw/serial: Switch to new trap handlers Andre Przywara
2021-02-16 14:31 ` Alexandru Elisei
2020-12-10 14:29 ` [PATCH kvmtool 15/21] vfio: Refactor ioport trap handler Andre Przywara
2021-02-16 14:47 ` Alexandru Elisei
2021-02-18 15:51 ` Andre Przywara
2020-12-10 14:29 ` [PATCH kvmtool 16/21] vfio: Switch to new ioport trap handlers Andre Przywara
2021-02-16 14:52 ` Alexandru Elisei
2020-12-10 14:29 ` [PATCH kvmtool 17/21] virtio: Switch trap handling to use MMIO handler Andre Przywara
2021-02-16 17:03 ` Alexandru Elisei
2021-02-18 16:13 ` Andre Przywara
2020-12-10 14:29 ` [PATCH kvmtool 18/21] pci: " Andre Przywara
2021-02-17 15:14 ` Alexandru Elisei
2020-12-10 14:29 ` [PATCH kvmtool 19/21] Remove ioport specific routines Andre Przywara
2021-02-17 15:49 ` Alexandru Elisei
2021-02-17 16:11 ` Alexandru Elisei
2021-02-18 16:34 ` Andre Przywara
2020-12-10 14:29 ` [PATCH kvmtool 20/21] hw/serial: ARM/arm64: Use MMIO at higher addresses Andre Przywara
2021-02-17 16:48 ` Alexandru Elisei
2021-02-18 12:18 ` Alexandru Elisei
2021-02-18 16:38 ` Andre Przywara
2020-12-10 14:29 ` [PATCH kvmtool 21/21] hw/rtc: " Andre Przywara
2021-02-18 13:33 ` Alexandru Elisei
2021-02-18 16:41 ` Andre Przywara [this message]
2021-02-10 17:44 ` [PATCH kvmtool 00/21] Unify I/O port and MMIO trap handling Alexandru Elisei
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