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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 00/25 v6] SBSA UART emulation support in Xen
Hi Bhupinder, I've tried this series today on an ARM64 platform. When I enable pl011 for the guest, I am not able to fully destroy the guest. It stay in zombie mode: 42sh> xl list Name ID Mem VCPUs State Time(s) Domain-0 0 3072 2 r----- 62.1 (null) 6 0 2 --p--d 1.5 It does not happen when I don't have pl011 enabled in the guest config. The step to reproduce it is: 42sh> xl create guest.cfg Parsing config from guest.cfg 42sh> xl list Name ID Mem VCPUs State Time(s) Domain-0 0 3072 2 r----- 12.9 guest 1 3265 1 r----- 0.1 42sh> xl destroy guest 42sh> xl list Name ID Mem VCPUs State Time(s) Domain-0 0 3072 2 r----- 14.9 (null) 1 0 1 --p--d 0.1 And my guest.cfg is: 42sh> cat guest.cfg kernel="/home/julien/works/guest/Image" name="guest" memory=3265 vcpus=2 vuart="sbsa_uart" I haven't dug into the problem but I would look at how you unmap the ring from Xen and xenconsole. Likely we still have a reference on it. Let me know if you need any help. Cheers, On 17/07/17 14:06, Bhupinder Thakur wrote: > SBSA UART emulation for guests in Xen > ====================================== > Linaro has published VM System specification for ARM Processors, which > provides a set of guidelines for both guest OS and hypervisor > implementations, > such that building OS images according to these guidelines guarantees > that those images can also run on hypervisors compliant with this > specification. > > One of the spec requirements is that the hypervisor must provide an > emulated SBSA UART as a serial console which meets the minimum requirements > in > SBSA UART as defined in appendix B of the following > ARM Server Base Architecture Document: > > https://static.docs.arm.com/den0029/a/Server_Base_System_Architecture_v3_1_ARM_DEN_0029A.pdf. > > This feature allows the Xen guests to use SBSA compliant pl011 UART as > as a console. > > Note that SBSA pl011 UART is a subset of full featured ARM pl011 UART and > supports only a subset of registers as mentioned below. It does not support > rx/tx DMA. > > Currently, Xen supports paravirtualized (aka PV console) and an emulated > serial > consoles. This feature will expose an emulated SBSA pl011 UART console to the > guest, which a user can access using xenconsole. > > The device tree passed to the guest VM will contain the pl011 MMIO address > range and an irq for receiving rx/tx pl011 interrupts. The device tree format > is specified in Documentation/devicetree/bindings/serial/arm_sbsa_uart.txt. > > The Xen hypervisor will expose two types of interfaces to the backend and > domU. > > The interface exposed to domU will be an emulated pl011 UART by emulating the > access to the following pl011 registers by the guest. > > - Data register (DR) - RW > - Raw interrupt status register (RIS) - RO > - Masked interrupt status register (MIS)- RO > - Interrupt Mask (IMSC) - RW > - Interrupt Clear (ICR) - WO > > It will also inject the pl011 interrupts to the guest in the following > conditions: > > - incoming data in the rx buffer for the guest > - there is space in the tx buffer for the guest to write more data > > The interface exposed to the backend will be the same PV console interface, > which minimizes the changes required in xenconsole to support a new pl011 > console. > > This interface has rx and tx ring buffers and an event channel for > sending/receiving events from the backend. > > So essentially Xen handles the data on behalf of domU and the backend. Any > data > written by domU is captured by Xen and written to the TX (OUT) ring buffer > and a pl011 event is raised to the backend to read the TX ring buffer. > > Similarly on reciving a pl011 event, Xen injects an interrupt to guest to > indicate there is data available in the RX (IN) ring buffer. > > The pl011 UART state is completely captured in the set of registers > mentioned above and this state is updated everytime there is an event from > the backend or there is register read/write access from domU. > > For example, if domU has masked the rx interrupt in the IMSC register, then > Xen > will not inject an interrupt to guest and will just update the RIS register. > Once the interrupt is unmasked by guest, the interrupt will be delivered to > the > guest. > > Changes summary: > > Xen Hypervisor > =============== > > 1. Add emulation code to emulate read/write access to pl011 registers and > pl011 > interrupts: > - It emulates DR read/write by reading and writing from/to the IN and > OUT ring buffers and raising an event to dom0 when there is data in > the OUT ring buffer and injecting an interrupt to the guest when there > is data in the IN ring buffer. > - Other registers are related to interrupt management and essentially > control when interrupts are delivered to the guest. > > 2. Add a new domctl API to initialize vpl011 emulation in Xen. > > 3. Enable vpl011 emulation for a domain based on a libxl option passed during > domain creation. > > Toolstack > ========== > > 1. Add a new option "vuart" in the domU configuration file to enable/disable > vuart. > > 2. Create a SBSA UART DT node in the guest device tree. It uses a fixed > vpl011 SPI IRQ number and MMIO address. > > 3. Call vpl011 init DOMCTL API to enable vpl011 emulation. > > 5. Add a new vuart xenstore node, which contains: > - ring-ref > - event channel > - buffer limit > - type > > Xenconsoled > ============ > > 1. Split the domain structure to support multiple consoles. > > 2. Modify different APIs such as buffer_append() etc. to operate on the > console structure. > > 3. Add support for handling multiple consoles. > > 4. Add support for vuart console: > > The vpl011 changes available at the following repo: > > url: https://git@xxxxxxxxxxxxxx:/people/bhupinder.thakur/xen.git > branch: vpl011_v6 > > Kindly wait for one day to checkout the code from the above URL. > > There are some TBD items which need to be looked at in the future: > > 1. Currently UEFI firmware logs the output to hvc console only. How can > UEFI firmware be made aware of pl011 console and how it can use it > as a console instead of hvc. > > There was a discussion on this and it was decided that SBSA UART should > be used as a debug port by the UEFI firmware so that all debug output > is redirected to this port. > > 2. Linux seems to have hvc console as the default console i.e. if no > console is specified then it uses hvc as the console. How can an > option be provided in Linux to select either hvc or pl011 as the > default console. > > It was suggeted to use the SPCR in ACPI and the stdout-path option in the > device tree to specify the default console. However, currently hvc console > is not describable in the ACPI/device tree. This support will have to be > added to allow the user to specify the default console. > > 3. ACPI support for pl011 device. > > CC: Ian Jackson <ian.jackson@xxxxxxxxxxxxx> > CC: Wei Liu <wei.liu2@xxxxxxxxxx> > CC: Stefano Stabellini <sstabellini@xxxxxxxxxx> > CC: Julien Grall <julien.grall@xxxxxxx> > CC: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> > > > Bhupinder Thakur (25): > xen/arm: vpl011: Define common ring buffer helper functions in > console.h > xen/arm: vpl011: Add SBSA UART emulation in Xen > xen/arm: vpl011: Allocate a new GFN in the toolstack for vuart > xen/arm: vpl011: Add support for vuart in libxl > xen/arm: vpl011: Rearrange xen header includes in alphabetical order > in domctl.c > xen/arm: vpl011: Add a new domctl API to initialize vpl011 > xen/arm: vpl011: Add a new vuart node in the xenstore > xen/arm: vpl011: Modify xenconsole to define and use a new console > structure > xen/arm: vpl011: Rename the console structure field conspath to xspath > xen/arm: vpl011: Modify xenconsole functions to take console structure > as input > xen/arm: vpl011: Add a new console_init function in xenconsole > xen/arm: vpl011: Add a new buffer_available function in xenconsole > xen/arm: vpl011: Add a new add_console_evtchn_fd function in > xenconsole > xen/arm: vpl011: Add a new add_console_tty_fd function in xenconsole > xen/arm: vpl011: Add a new console_evtchn_unmask function in > xenconsole > xen/arm: vpl011: Add a new handle_console_ring function in xenconsole > xen/arm: vpl011: Add a new handle_console_tty function in xenconsole > xen/arm: vpl011: Add a new console_cleanup function in xenconsole > xen/arm: vpl011: Add a new console_open_log function in xenconsole > xen/arm: vpl011: Add a new console_close_evtchn function in xenconsole > xen/arm: vpl011: Add support for multiple consoles in xenconsole > xen/arm: vpl011: Add support for vuart console in xenconsole > xen/arm: vpl011: Add a new vuart console type to xenconsole client > xen/arm: vpl011: Add a pl011 uart DT node in the guest device tree > xen/arm: vpl011: Update documentation for vuart console support > > config/arm32.mk | 1 + > config/arm64.mk | 1 + > docs/man/xl.cfg.pod.5.in | 9 + > docs/misc/console.txt | 44 ++- > tools/console/Makefile | 3 +- > tools/console/client/main.c | 13 +- > tools/console/daemon/io.c | 662 > ++++++++++++++++++++++++----------- > tools/libxc/include/xc_dom.h | 2 + > tools/libxc/include/xenctrl.h | 18 + > tools/libxc/xc_dom_arm.c | 5 +- > tools/libxc/xc_dom_boot.c | 2 + > tools/libxc/xc_domain.c | 24 ++ > tools/libxl/libxl.h | 6 + > tools/libxl/libxl_arch.h | 6 + > tools/libxl/libxl_arm.c | 72 +++- > tools/libxl/libxl_console.c | 47 +++ > tools/libxl/libxl_create.c | 9 +- > tools/libxl/libxl_device.c | 9 +- > tools/libxl/libxl_dom.c | 5 + > tools/libxl/libxl_internal.h | 6 + > tools/libxl/libxl_types.idl | 7 + > tools/libxl/libxl_types_internal.idl | 1 + > tools/libxl/libxl_x86.c | 8 + > tools/xl/xl_cmdtable.c | 2 +- > tools/xl/xl_console.c | 5 +- > tools/xl/xl_parse.c | 8 + > xen/arch/arm/Kconfig | 7 + > xen/arch/arm/Makefile | 1 + > xen/arch/arm/domain.c | 5 + > xen/arch/arm/domctl.c | 43 ++- > xen/arch/arm/vpl011.c | 455 ++++++++++++++++++++++++ > xen/include/asm-arm/domain.h | 6 + > xen/include/asm-arm/pl011-uart.h | 2 + > xen/include/asm-arm/vpl011.h | 72 ++++ > xen/include/public/arch-arm.h | 6 + > xen/include/public/domctl.h | 21 ++ > xen/include/public/io/console.h | 4 + > 37 files changed, 1360 insertions(+), 237 deletions(-) > create mode 100644 xen/arch/arm/vpl011.c > create mode 100644 xen/include/asm-arm/vpl011.h > -- Julien Grall _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx https://lists.xen.org/xen-devel
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