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SubjectRe: [PATCH] x86/ioperm: add new paravirt function update_io_bitmap
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Friendly ping...

On 18.02.20 16:47, Juergen Gross wrote:
> Commit 111e7b15cf10f6 ("x86/ioperm: Extend IOPL config to control
> ioperm() as well") reworked the iopl syscall to use I/O bitmaps.
>
> Unfortunately this broke Xen PV domains using that syscall as there
> is currently no I/O bitmap support in PV domains.
>
> Add I/O bitmap support via a new paravirt function update_io_bitmap
> which Xen PV domains can use to update their I/O bitmaps via a
> hypercall.
>
> Fixes: 111e7b15cf10f6 ("x86/ioperm: Extend IOPL config to control ioperm() as well")
> Reported-by: Jan Beulich <jbeulich@suse.com>
> Cc: <stable@vger.kernel.org> # 5.5
> Signed-off-by: Juergen Gross <jgross@suse.com>
> Reviewed-by: Jan Beulich <jbeulich@suse.com>
> Tested-by: Jan Beulich <jbeulich@suse.com>
> ---
> arch/x86/include/asm/io_bitmap.h | 9 ++++++++-
> arch/x86/include/asm/paravirt.h | 7 +++++++
> arch/x86/include/asm/paravirt_types.h | 4 ++++
> arch/x86/kernel/paravirt.c | 5 +++++
> arch/x86/kernel/process.c | 2 +-
> arch/x86/xen/enlighten_pv.c | 25 +++++++++++++++++++++++++
> 6 files changed, 50 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/include/asm/io_bitmap.h b/arch/x86/include/asm/io_bitmap.h
> index 02c6ef8f7667..07344d82e88e 100644
> --- a/arch/x86/include/asm/io_bitmap.h
> +++ b/arch/x86/include/asm/io_bitmap.h
> @@ -19,7 +19,14 @@ struct task_struct;
> void io_bitmap_share(struct task_struct *tsk);
> void io_bitmap_exit(void);
>
> -void tss_update_io_bitmap(void);
> +void native_tss_update_io_bitmap(void);
> +
> +#ifdef CONFIG_PARAVIRT_XXL
> +#include <asm/paravirt.h>
> +#else
> +#define tss_update_io_bitmap native_tss_update_io_bitmap
> +#endif
> +
> #else
> static inline void io_bitmap_share(struct task_struct *tsk) { }
> static inline void io_bitmap_exit(void) { }
> diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
> index 86e7317eb31f..694d8daf4983 100644
> --- a/arch/x86/include/asm/paravirt.h
> +++ b/arch/x86/include/asm/paravirt.h
> @@ -295,6 +295,13 @@ static inline void write_idt_entry(gate_desc *dt, int entry, const gate_desc *g)
> PVOP_VCALL3(cpu.write_idt_entry, dt, entry, g);
> }
>
> +#ifdef CONFIG_X86_IOPL_IOPERM
> +static inline void tss_update_io_bitmap(void)
> +{
> + PVOP_VCALL0(cpu.update_io_bitmap);
> +}
> +#endif
> +
> static inline void paravirt_activate_mm(struct mm_struct *prev,
> struct mm_struct *next)
> {
> diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
> index 84812964d3dd..732f62e04ddb 100644
> --- a/arch/x86/include/asm/paravirt_types.h
> +++ b/arch/x86/include/asm/paravirt_types.h
> @@ -140,6 +140,10 @@ struct pv_cpu_ops {
>
> void (*load_sp0)(unsigned long sp0);
>
> +#ifdef CONFIG_X86_IOPL_IOPERM
> + void (*update_io_bitmap)(void);
> +#endif
> +
> void (*wbinvd)(void);
>
> /* cpuid emulation, mostly so that caps bits can be disabled */
> diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
> index 789f5e4f89de..c131ba4e70ef 100644
> --- a/arch/x86/kernel/paravirt.c
> +++ b/arch/x86/kernel/paravirt.c
> @@ -30,6 +30,7 @@
> #include <asm/timer.h>
> #include <asm/special_insns.h>
> #include <asm/tlb.h>
> +#include <asm/io_bitmap.h>
>
> /*
> * nop stub, which must not clobber anything *including the stack* to
> @@ -341,6 +342,10 @@ struct paravirt_patch_template pv_ops = {
> .cpu.iret = native_iret,
> .cpu.swapgs = native_swapgs,
>
> +#ifdef CONFIG_X86_IOPL_IOPERM
> + .cpu.update_io_bitmap = native_tss_update_io_bitmap,
> +#endif
> +
> .cpu.start_context_switch = paravirt_nop,
> .cpu.end_context_switch = paravirt_nop,
>
> diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
> index 839b5244e3b7..3053c85e0e42 100644
> --- a/arch/x86/kernel/process.c
> +++ b/arch/x86/kernel/process.c
> @@ -374,7 +374,7 @@ static void tss_copy_io_bitmap(struct tss_struct *tss, struct io_bitmap *iobm)
> /**
> * tss_update_io_bitmap - Update I/O bitmap before exiting to usermode
> */
> -void tss_update_io_bitmap(void)
> +void native_tss_update_io_bitmap(void)
> {
> struct tss_struct *tss = this_cpu_ptr(&cpu_tss_rw);
> struct thread_struct *t = &current->thread;
> diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
> index 1f756ffffe8b..feaf2e68ee5c 100644
> --- a/arch/x86/xen/enlighten_pv.c
> +++ b/arch/x86/xen/enlighten_pv.c
> @@ -72,6 +72,9 @@
> #include <asm/mwait.h>
> #include <asm/pci_x86.h>
> #include <asm/cpu.h>
> +#ifdef CONFIG_X86_IOPL_IOPERM
> +#include <asm/io_bitmap.h>
> +#endif
>
> #ifdef CONFIG_ACPI
> #include <linux/acpi.h>
> @@ -837,6 +840,25 @@ static void xen_load_sp0(unsigned long sp0)
> this_cpu_write(cpu_tss_rw.x86_tss.sp0, sp0);
> }
>
> +#ifdef CONFIG_X86_IOPL_IOPERM
> +static void xen_update_io_bitmap(void)
> +{
> + struct physdev_set_iobitmap iobitmap;
> + struct tss_struct *tss = this_cpu_ptr(&cpu_tss_rw);
> +
> + native_tss_update_io_bitmap();
> +
> + iobitmap.bitmap = (uint8_t *)(&tss->x86_tss) +
> + tss->x86_tss.io_bitmap_base;
> + if (tss->x86_tss.io_bitmap_base == IO_BITMAP_OFFSET_INVALID)
> + iobitmap.nr_ports = 0;
> + else
> + iobitmap.nr_ports = IO_BITMAP_BITS;
> +
> + HYPERVISOR_physdev_op(PHYSDEVOP_set_iobitmap, &iobitmap);
> +}
> +#endif
> +
> static void xen_io_delay(void)
> {
> }
> @@ -1046,6 +1068,9 @@ static const struct pv_cpu_ops xen_cpu_ops __initconst = {
> .write_idt_entry = xen_write_idt_entry,
> .load_sp0 = xen_load_sp0,
>
> +#ifdef CONFIG_X86_IOPL_IOPERM
> + .update_io_bitmap = xen_update_io_bitmap,
> +#endif
> .io_delay = xen_io_delay,
>
> /* Xen takes care of %gs when switching to usermode for us */
>

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