Google
  Web www.spinics.net

Re: [PATCH v4 1/3] KVM: PPC: epapr: Factor out the epapr init

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]



On 16.02.2012, at 10:26, Liu Yu <yu.liu@xxxxxxxxxxxxx> wrote:

> from the kvm guest paravirt init code.
> 
> Signed-off-by: Liu Yu <yu.liu@xxxxxxxxxxxxx>
> ---
> v4:
> 1. code cleanup
> 2. move kvm_hypercall_start() to epapr_hypercall_start()
> 
> arch/powerpc/Kconfig                    |    4 ++
> arch/powerpc/include/asm/epapr_hcalls.h |    2 +
> arch/powerpc/kernel/Makefile            |    1 +
> arch/powerpc/kernel/epapr.S             |   25 ++++++++++++++++
> arch/powerpc/kernel/epapr_para.c        |   49 +++++++++++++++++++++++++++++++
> arch/powerpc/kernel/kvm.c               |   28 ++----------------
> arch/powerpc/kernel/kvm_emul.S          |   10 ------
> arch/powerpc/kvm/Kconfig                |    1 +
> 8 files changed, 85 insertions(+), 35 deletions(-)
> create mode 100644 arch/powerpc/kernel/epapr.S
> create mode 100644 arch/powerpc/kernel/epapr_para.c
> 
> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> index 1919634..1262b43 100644
> --- a/arch/powerpc/Kconfig
> +++ b/arch/powerpc/Kconfig
> @@ -202,6 +202,10 @@ config EPAPR_BOOT
>      Used to allow a board to specify it wants an ePAPR compliant wrapper.
>    default n
> 
> +config EPAPR_PARAVIRT
> +    bool
> +    default n
> +
> config DEFAULT_UIMAGE
>    bool
>    help
> diff --git a/arch/powerpc/include/asm/epapr_hcalls.h b/arch/powerpc/include/asm/epapr_hcalls.h
> index f3b0c2c..0ff3f24 100644
> --- a/arch/powerpc/include/asm/epapr_hcalls.h
> +++ b/arch/powerpc/include/asm/epapr_hcalls.h
> @@ -148,6 +148,8 @@
> #define EV_HCALL_CLOBBERS2 EV_HCALL_CLOBBERS3, "r5"
> #define EV_HCALL_CLOBBERS1 EV_HCALL_CLOBBERS2, "r4"
> 
> +extern bool epapr_para_enabled;
> +extern u32 epapr_hypercall_start[];
> 
> /*
>  * We use "uintptr_t" to define a register because it's guaranteed to be a
> diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
> index ee728e4..9e807f3 100644
> --- a/arch/powerpc/kernel/Makefile
> +++ b/arch/powerpc/kernel/Makefile
> @@ -136,6 +136,7 @@ ifneq ($(CONFIG_XMON)$(CONFIG_KEXEC),)
> obj-y                += ppc_save_regs.o
> endif
> 
> +obj-$(CONFIG_EPAPR_PARAVIRT)    += epapr_para.o epapr.o
> obj-$(CONFIG_KVM_GUEST)        += kvm.o kvm_emul.o
> 
> # Disable GCOV in odd or sensitive code
> diff --git a/arch/powerpc/kernel/epapr.S b/arch/powerpc/kernel/epapr.S
> new file mode 100644
> index 0000000..697b390
> --- /dev/null
> +++ b/arch/powerpc/kernel/epapr.S
> @@ -0,0 +1,25 @@
> +/*
> + * Copyright (C) 2012 Freescale Semiconductor, Inc.
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License
> + * as published by the Free Software Foundation; either version
> + * 2 of the License, or (at your option) any later version.
> + */
> +
> +#include <linux/threads.h>
> +#include <asm/reg.h>
> +#include <asm/page.h>
> +#include <asm/cputable.h>
> +#include <asm/thread_info.h>
> +#include <asm/ppc_asm.h>
> +#include <asm/asm-offsets.h>
> +
> +/* Hypercall entry point. Will be patched with device tree instructions. */
> +.global epapr_hypercall_start
> +epapr_hypercall_start:
> +    li    r3, -1
> +    nop
> +    nop
> +    nop
> +    blr
> diff --git a/arch/powerpc/kernel/epapr_para.c b/arch/powerpc/kernel/epapr_para.c
> new file mode 100644
> index 0000000..ea13cac
> --- /dev/null
> +++ b/arch/powerpc/kernel/epapr_para.c
> @@ -0,0 +1,49 @@
> +/*
> + * ePAPR para-virtualization support.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License, version 2, as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
> + *
> + * Copyright (C) 2012 Freescale Semiconductor, Inc.
> + */
> +
> +#include <linux/of.h>
> +#include <asm/epapr_hcalls.h>
> +#include <asm/cacheflush.h>
> +
> +bool epapr_para_enabled = false;
> +
> +static int __init epapr_para_init(void)
> +{
> +    struct device_node *hyper_node;
> +    const u32 *insts;
> +    int len, i;
> +
> +    hyper_node = of_find_node_by_path("/hypervisor");
> +    if (!hyper_node)
> +        return -ENODEV;
> +
> +    insts = of_get_property(hyper_node, "hcall-instructions", &len);
> +    if (!(len % 4) && (len >= (4 * 4))) {
> +        for (i = 0; i < (len / 4); i++)

So if the dt passes in less than 4 ops, you bail out, and for more you overwrite the buffer? Not good :)

> +            epapr_hypercall_start[i] = insts[i];
> +        flush_icache_range((ulong)epapr_hypercall_start,
> +                           (ulong)epapr_hypercall_start + len);
> +
> +        epapr_para_enabled = true;
> +    }
> +
> +    return 0;
> +}
> +
> +early_initcall(epapr_para_init);
> diff --git a/arch/powerpc/kernel/kvm.c b/arch/powerpc/kernel/kvm.c
> index 62bdf23..9dfc24a 100644
> --- a/arch/powerpc/kernel/kvm.c
> +++ b/arch/powerpc/kernel/kvm.c
> @@ -31,6 +31,7 @@
> #include <asm/cacheflush.h>
> #include <asm/disassemble.h>
> #include <asm/ppc-opcode.h>
> +#include <asm/epapr_hcalls.h>
> 
> #define KVM_MAGIC_PAGE        (-4096L)
> #define magic_var(x) KVM_MAGIC_PAGE + offsetof(struct kvm_vcpu_arch_shared, x)
> @@ -726,7 +727,7 @@ unsigned long kvm_hypercall(unsigned long *in,
>    unsigned long register r11 asm("r11") = nr;
>    unsigned long register r12 asm("r12");
> 
> -    asm volatile("bl    kvm_hypercall_start"
> +    asm volatile("bl    epapr_hypercall_start"
>             : "=r"(r0), "=r"(r3), "=r"(r4), "=r"(r5), "=r"(r6),
>               "=r"(r7), "=r"(r8), "=r"(r9), "=r"(r10), "=r"(r11),
>               "=r"(r12)
> @@ -747,29 +748,6 @@ unsigned long kvm_hypercall(unsigned long *in,
> }
> EXPORT_SYMBOL_GPL(kvm_hypercall);
> 
> -static int kvm_para_setup(void)
> -{
> -    extern u32 kvm_hypercall_start;
> -    struct device_node *hyper_node;
> -    u32 *insts;
> -    int len, i;
> -
> -    hyper_node = of_find_node_by_path("/hypervisor");
> -    if (!hyper_node)
> -        return -1;
> -
> -    insts = (u32*)of_get_property(hyper_node, "hcall-instructions", &len);
> -    if (len % 4)
> -        return -1;
> -    if (len > (4 * 4))

As you can see, the previous code allowed for less than 4 instructions, but not more.

Alex

> -        return -1;
> -
> -    for (i = 0; i < (len / 4); i++)
> -        kvm_patch_ins(&(&kvm_hypercall_start)[i], insts[i]);
> -
> -    return 0;
> -}
> -
> static __init void kvm_free_tmp(void)
> {
>    unsigned long start, end;
> @@ -791,7 +769,7 @@ static int __init kvm_guest_init(void)
>    if (!kvm_para_available())
>        goto free_tmp;
> 
> -    if (kvm_para_setup())
> +    if (!epapr_para_enabled)
>        goto free_tmp;
> 
>    if (kvm_para_has_feature(KVM_FEATURE_MAGIC_PAGE))
> diff --git a/arch/powerpc/kernel/kvm_emul.S b/arch/powerpc/kernel/kvm_emul.S
> index e291cf3..62ceb2a 100644
> --- a/arch/powerpc/kernel/kvm_emul.S
> +++ b/arch/powerpc/kernel/kvm_emul.S
> @@ -24,16 +24,6 @@
> #include <asm/page.h>
> #include <asm/asm-offsets.h>
> 
> -/* Hypercall entry point. Will be patched with device tree instructions. */
> -
> -.global kvm_hypercall_start
> -kvm_hypercall_start:
> -    li    r3, -1
> -    nop
> -    nop
> -    nop
> -    blr
> -
> #define KVM_MAGIC_PAGE        (-4096)
> 
> #ifdef CONFIG_64BIT
> diff --git a/arch/powerpc/kvm/Kconfig b/arch/powerpc/kvm/Kconfig
> index 8f64709..9bb9d18 100644
> --- a/arch/powerpc/kvm/Kconfig
> +++ b/arch/powerpc/kvm/Kconfig
> @@ -20,6 +20,7 @@ config KVM
>    bool
>    select PREEMPT_NOTIFIERS
>    select ANON_INODES
> +    select EPAPR_PARAVIRT
> 
> config KVM_BOOK3S_HANDLER
>    bool
> -- 
> 1.7.0.4
> 
> 
> --
> To unsubscribe from this list: send the line "unsubscribe kvm" in
> the body of a message to majordomo@xxxxxxxxxxxxxxx
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
--
To unsubscribe from this list: send the line "unsubscribe kvm-ppc" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html


[KVM Development]     [KVM ARM]     [KVM ia64]     [Linux USB Devel]     [Linux Video]     [Linux Audio Users]     [Photo]     [Video Projectors]     [PDAs]     [Free Online Dating]     [Linux Kernel]     [Linux SCSI]     [XFree86]     [Big List of Linux Books]

  Powered by Linux