From: Peter Maydell <peter.maydell@linaro.org>
To: Salil Mehta <salil.mehta@huawei.com>
Cc: qemu-devel@nongnu.org, qemu-arm@nongnu.org, maz@kernel.org,
jean-philippe@linaro.org, jonathan.cameron@huawei.com,
lpieralisi@kernel.org, richard.henderson@linaro.org,
imammedo@redhat.com, andrew.jones@linux.dev, david@redhat.com,
philmd@linaro.org, eric.auger@redhat.com,
oliver.upton@linux.dev, pbonzini@redhat.com, mst@redhat.com,
will@kernel.org, gshan@redhat.com, rafael@kernel.org,
alex.bennee@linaro.org, linux@armlinux.org.uk,
darren@os.amperecomputing.com, ilkka@os.amperecomputing.com,
vishnu@os.amperecomputing.com, karl.heubaum@oracle.com,
miguel.luis@oracle.com, salil.mehta@opnsrc.net,
zhukeqian1@huawei.com, wangxiongfeng2@huawei.com,
wangyanan55@huawei.com, jiakernel2@gmail.com,
maobibo@loongson.cn, lixianglai@loongson.cn,
linuxarm@huawei.com
Subject: Re: [PATCH V8 6/8] physmem: Add helper function to destroy CPU AddressSpace
Date: Sat, 4 May 2024 14:40:49 +0100 [thread overview]
Message-ID: <CAFEAcA93EotG4-LXRJF034_9dWAWgZJA1VF6dB-xCsXn0T059g@mail.gmail.com> (raw)
In-Reply-To: <20240312020000.12992-7-salil.mehta@huawei.com>
On Tue, 12 Mar 2024 at 02:02, Salil Mehta <salil.mehta@huawei.com> wrote:
>
> Virtual CPU Hot-unplug leads to unrealization of a CPU object. This also
> involves destruction of the CPU AddressSpace. Add common function to help
> destroy the CPU AddressSpace.
>
> Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
> Tested-by: Vishnu Pajjuri <vishnu@os.amperecomputing.com>
> Reviewed-by: Gavin Shan <gshan@redhat.com>
> Tested-by: Xianglai Li <lixianglai@loongson.cn>
> Tested-by: Miguel Luis <miguel.luis@oracle.com>
> Reviewed-by: Shaoqin Huang <shahuang@redhat.com>
> diff --git a/system/physmem.c b/system/physmem.c
> index 6e9ed97597..61b32ac4f2 100644
> --- a/system/physmem.c
> +++ b/system/physmem.c
> @@ -761,6 +761,7 @@ void cpu_address_space_init(CPUState *cpu, int asidx,
>
> if (!cpu->cpu_ases) {
> cpu->cpu_ases = g_new0(CPUAddressSpace, cpu->num_ases);
> + cpu->cpu_ases_count = cpu->num_ases;
> }
>
> newas = &cpu->cpu_ases[asidx];
> @@ -774,6 +775,34 @@ void cpu_address_space_init(CPUState *cpu, int asidx,
> }
> }
>
> +void cpu_address_space_destroy(CPUState *cpu, int asidx)
> +{
> + CPUAddressSpace *cpuas;
> +
> + assert(cpu->cpu_ases);
> + assert(asidx >= 0 && asidx < cpu->num_ases);
> + /* KVM cannot currently support multiple address spaces. */
> + assert(asidx == 0 || !kvm_enabled());
> +
> + cpuas = &cpu->cpu_ases[asidx];
> + if (tcg_enabled()) {
> + memory_listener_unregister(&cpuas->tcg_as_listener);
> + }
> +
> + address_space_destroy(cpuas->as);
> + g_free_rcu(cpuas->as, rcu);
> +
> + if (asidx == 0) {
> + /* reset the convenience alias for address space 0 */
> + cpu->as = NULL;
> + }
> +
> + if (--cpu->cpu_ases_count == 0) {
> + g_free(cpu->cpu_ases);
> + cpu->cpu_ases = NULL;
> + }
> +}
When do we need to destroy a single address space in this way
that means we need to keep a count of how many ASes the CPU
currently has? The commit message talks about the case when we
unrealize the whole CPU object, but in that situation you can
just throw away all the ASes at once (eg by calling some
cpu_destroy_address_spaces() function from cpu_common_unrealizefn()).
Also, if we're leaking stuff here by failing to destroy it,
is that a problem for existing CPU types like x86 that we
can already hotplug?
thanks
-- PMM
next prev parent reply other threads:[~2024-05-04 13:41 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-12 1:59 [PATCH V8 0/8] Add architecture agnostic code to support vCPU Hotplug Salil Mehta via
2024-03-12 1:59 ` [PATCH V8 1/8] accel/kvm: Extract common KVM vCPU {creation, parking} code Salil Mehta via
2024-03-22 8:15 ` Harsh Prateek Bora
2024-04-23 6:44 ` Harsh Prateek Bora
2024-05-03 18:56 ` Salil Mehta via
2024-05-03 18:43 ` Salil Mehta via
2024-04-04 13:59 ` [PATCH V8 1/8] accel/kvm: Extract common KVM vCPU {creation,parking} code Vishnu Pajjuri
2024-05-03 16:23 ` Salil Mehta via
2024-05-07 12:39 ` Vishnu Pajjuri
2024-05-07 12:51 ` Salil Mehta
2024-05-03 9:40 ` Philippe Mathieu-Daudé
2024-05-03 15:57 ` Salil Mehta via
2024-05-03 18:22 ` Philippe Mathieu-Daudé
2024-05-08 10:46 ` Salil Mehta via
2024-05-10 14:43 ` Philippe Mathieu-Daudé
2024-03-12 1:59 ` [PATCH V8 2/8] hw/acpi: Move CPU ctrl-dev MMIO region len macro to common header file Salil Mehta via
2024-03-12 1:59 ` [PATCH V8 3/8] hw/acpi: Update ACPI GED framework to support vCPU Hotplug Salil Mehta via
2024-03-13 6:14 ` Zhao Liu
2024-05-03 19:59 ` Salil Mehta via
2024-05-06 9:05 ` Zhao Liu
2024-05-06 9:27 ` Salil Mehta via
2024-04-04 14:01 ` Vishnu Pajjuri
2024-05-03 20:09 ` Salil Mehta via
2024-03-12 1:59 ` [PATCH V8 4/8] hw/acpi: Update GED _EVT method AML with CPU scan Salil Mehta via
2024-03-12 1:59 ` [PATCH V8 5/8] hw/acpi: Update CPUs AML with cpu-(ctrl)dev change Salil Mehta via
2024-03-12 1:59 ` [PATCH V8 6/8] physmem: Add helper function to destroy CPU AddressSpace Salil Mehta via
2024-03-15 1:16 ` 答复: " zhukeqian via
2024-05-04 1:40 ` Salil Mehta
2024-05-04 13:40 ` Peter Maydell [this message]
2024-05-06 9:06 ` Salil Mehta via
2024-05-06 9:28 ` Peter Maydell
2024-05-07 0:11 ` Salil Mehta via
2024-05-07 9:02 ` Peter Maydell
2024-05-07 9:56 ` Salil Mehta via
2024-03-12 1:59 ` [PATCH V8 7/8] gdbstub: Add helper function to unregister GDB register space Salil Mehta via
2024-04-04 14:02 ` Vishnu Pajjuri
2024-05-03 19:36 ` Salil Mehta via
2024-03-12 2:00 ` [PATCH V8 8/8] docs/specs/acpi_hw_reduced_hotplug: Add the CPU Hotplug Event Bit Salil Mehta via
2024-03-12 18:00 ` [PATCH V8 0/8] Add architecture agnostic code to support vCPU Hotplug Michael S. Tsirkin
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