Commit 99bcd4a6 authored by Juergen Gross's avatar Juergen Gross Committed by Thomas Gleixner
Browse files

x86/ioperm: Add new paravirt function update_io_bitmap() 



Commit 111e7b15 ("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: 111e7b15 ("x86/ioperm: Extend IOPL config to control ioperm() as well")
Reported-by: default avatarJan Beulich <jbeulich@suse.com>
Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Tested-by: default avatarJan Beulich <jbeulich@suse.com>
Reviewed-by: default avatarJan Beulich <jbeulich@suse.com>
Cc: <stable@vger.kernel.org> # 5.5
Link: https://lkml.kernel.org/r/20200218154712.25490-1-jgross@suse.com
parent 735a6dd0

arch/x86/include/asm/io_bitmap.h

+8 −1
Original line number Diff line number Diff line
@@ -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) { }

arch/x86/include/asm/paravirt.h

+7 −0
Original line number Diff line number Diff line
@@ -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)

{

arch/x86/include/asm/paravirt_types.h

+4 −0
Original line number Diff line number Diff line
@@ -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 */

arch/x86/kernel/paravirt.c

+5 −0
Original line number Diff line number Diff line
@@ -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,

arch/x86/kernel/process.c

+1 −1
Original line number Diff line number Diff line
@@ -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;

CRA Git | Maintained and supported by SUSTech CRA and CCSE