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Re: [Qemu-devel] [Qemu-arm] [PATCH 4/8] boards.h: Define new flag ignore
From: |
Edgar E. Iglesias |
Subject: |
Re: [Qemu-devel] [Qemu-arm] [PATCH 4/8] boards.h: Define new flag ignore_memory_transaction_failures |
Date: |
Sat, 5 Aug 2017 03:23:43 +0200 |
User-agent: |
Mutt/1.5.24 (2015-08-30) |
On Fri, Aug 04, 2017 at 06:20:45PM +0100, Peter Maydell wrote:
> Define a new MachineClass field ignore_memory_transaction_failures.
> If this is flag is true then the CPU will ignore memory transaction
> failures which should cause the CPU to take an exception due to an
> access to an unassigned physical address; the transaction will
> instead return zero (for a read) or be ignored (for a write). This
> should be set only by legacy board models which rely on the old
> RAZ/WI behaviour for handling devices that QEMU does not yet model.
> New board models should instead use "unimplemented-device" for all
> memory ranges where the guest will attempt to probe for a device that
> QEMU doesn't implement and a stub device is required.
>
> We need this for ARM boards, where we're about to implement support for
> generating external aborts on memory transaction failures. Too many
> of our legacy board models rely on the RAZ/WI behaviour and we
> would break currently working guests when their "probe for device"
> code provoked an external abort rather than a RAZ.
>
> Signed-off-by: Peter Maydell <address@hidden>
Reviewed-by: Edgar E. Iglesias <address@hidden>
> ---
> include/hw/boards.h | 11 +++++++++++
> include/qom/cpu.h | 7 ++++++-
> qom/cpu.c | 7 +++++++
> 3 files changed, 24 insertions(+), 1 deletion(-)
>
> diff --git a/include/hw/boards.h b/include/hw/boards.h
> index 3363dd1..7f044d1 100644
> --- a/include/hw/boards.h
> +++ b/include/hw/boards.h
> @@ -131,6 +131,16 @@ typedef struct {
> * size than the target architecture's minimum. (Attempting to create
> * such a CPU will fail.) Note that changing this is a migration
> * compatibility break for the machine.
> + * @ignore_memory_transaction_failures:
> + * If this is flag is true then the CPU will ignore memory transaction
> + * failures which should cause the CPU to take an exception due to an
> + * access to an unassigned physical address; the transaction will instead
> + * return zero (for a read) or be ignored (for a write). This should be
> + * set only by legacy board models which rely on the old RAZ/WI behaviour
> + * for handling devices that QEMU does not yet model. New board models
> + * should instead use "unimplemented-device" for all memory ranges where
> + * the guest will attempt to probe for a device that QEMU doesn't
> + * implement and a stub device is required.
> */
> struct MachineClass {
> /*< private >*/
> @@ -171,6 +181,7 @@ struct MachineClass {
> bool rom_file_has_mr;
> int minimum_page_bits;
> bool has_hotpluggable_cpus;
> + bool ignore_memory_transaction_failures;
> int numa_mem_align_shift;
> void (*numa_auto_assign_ram)(MachineClass *mc, NodeInfo *nodes,
> int nb_nodes, ram_addr_t size);
> diff --git a/include/qom/cpu.h b/include/qom/cpu.h
> index fc54d55..8cff86f 100644
> --- a/include/qom/cpu.h
> +++ b/include/qom/cpu.h
> @@ -311,6 +311,9 @@ struct qemu_work_item;
> * @trace_dstate_delayed: Delayed changes to trace_dstate (includes all
> changes
> * to @trace_dstate).
> * @trace_dstate: Dynamic tracing state of events for this vCPU (bitmask).
> + * @ignore_memory_transaction_failures: Cached copy of the MachineState
> + * flag of the same name: allows the board to suppress calling of the
> + * CPU do_transaction_failed hook function.
> *
> * State of one CPU core or thread.
> */
> @@ -397,6 +400,8 @@ struct CPUState {
> */
> bool throttle_thread_scheduled;
>
> + bool ignore_memory_transaction_failures;
> +
> /* Note that this is accessed at the start of every TB via a negative
> offset from AREG0. Leave this field at the end so as to make the
> (absolute value) offset as small as possible. This reduces code
> @@ -853,7 +858,7 @@ static inline void cpu_transaction_failed(CPUState *cpu,
> hwaddr physaddr,
> {
> CPUClass *cc = CPU_GET_CLASS(cpu);
>
> - if (cc->do_transaction_failed) {
> + if (!cpu->ignore_memory_transaction_failures &&
> cc->do_transaction_failed) {
> cc->do_transaction_failed(cpu, physaddr, addr, size, access_type,
> mmu_idx, attrs, response, retaddr);
> }
> diff --git a/qom/cpu.c b/qom/cpu.c
> index 4f38db0..d8dcf64 100644
> --- a/qom/cpu.c
> +++ b/qom/cpu.c
> @@ -29,6 +29,7 @@
> #include "exec/cpu-common.h"
> #include "qemu/error-report.h"
> #include "sysemu/sysemu.h"
> +#include "hw/boards.h"
> #include "hw/qdev-properties.h"
> #include "trace-root.h"
>
> @@ -360,6 +361,12 @@ static void cpu_common_parse_features(const char
> *typename, char *features,
> static void cpu_common_realizefn(DeviceState *dev, Error **errp)
> {
> CPUState *cpu = CPU(dev);
> + Object *machine = qdev_get_machine();
> + ObjectClass *oc = object_get_class(machine);
> + MachineClass *mc = MACHINE_CLASS(oc);
> +
> + cpu->ignore_memory_transaction_failures =
> + mc->ignore_memory_transaction_failures;
>
> if (dev->hotplugged) {
> cpu_synchronize_post_init(cpu);
> --
> 2.7.4
>
>
- [Qemu-devel] [PATCH 4/8] boards.h: Define new flag ignore_memory_transaction_failures, (continued)
- [Qemu-devel] [PATCH 4/8] boards.h: Define new flag ignore_memory_transaction_failures, Peter Maydell, 2017/08/04
- Re: [Qemu-devel] [Qemu-arm] [PATCH 4/8] boards.h: Define new flag ignore_memory_transaction_failures, Philippe Mathieu-Daudé, 2017/08/04
- Re: [Qemu-devel] [Qemu-arm] [PATCH 4/8] boards.h: Define new flag ignore_memory_transaction_failures, Richard Henderson, 2017/08/04
- Re: [Qemu-devel] [Qemu-arm] [PATCH 4/8] boards.h: Define new flag ignore_memory_transaction_failures, Peter Maydell, 2017/08/05
- Re: [Qemu-devel] [Qemu-arm] [PATCH 4/8] boards.h: Define new flag ignore_memory_transaction_failures, Peter Maydell, 2017/08/17
- Re: [Qemu-devel] [Qemu-arm] [PATCH 4/8] boards.h: Define new flag ignore_memory_transaction_failures, Philippe Mathieu-Daudé, 2017/08/21
- Re: [Qemu-devel] [Qemu-arm] [PATCH 4/8] boards.h: Define new flag ignore_memory_transaction_failures, Peter Maydell, 2017/08/22
- Message not available
- Re: [Qemu-devel] [Qemu-arm] [PATCH 4/8] boards.h: Define new flag ignore_memory_transaction_failures, Richard Henderson, 2017/08/24
- Re: [Qemu-devel] [Qemu-arm] [PATCH 4/8] boards.h: Define new flag ignore_memory_transaction_failures, Peter Maydell, 2017/08/25
- Re: [Qemu-devel] [Qemu-arm] [PATCH 4/8] boards.h: Define new flag ignore_memory_transaction_failures, Peter Maydell, 2017/08/05
Re: [Qemu-devel] [Qemu-arm] [PATCH 4/8] boards.h: Define new flag ignore_memory_transaction_failures,
Edgar E. Iglesias <=
[Qemu-devel] [PATCH 1/8] memory.h: Move MemTxResult type to memattrs.h, Peter Maydell, 2017/08/04
[Qemu-devel] [PATCH 3/8] cputlb: Support generating CPU exceptions on memory transaction failures, Peter Maydell, 2017/08/04
[Qemu-devel] [PATCH 5/8] hw/arm: Set ignore_memory_transaction_failures for most ARM boards, Peter Maydell, 2017/08/04