Re: [PATCH 17/27] Make head_64.S aware of KVM real mode code

From: Benjamin Herrenschmidt <benh-XVmvHMARGAS8U2dJNN8I7kB+6BGkLq7r@public.gmane.org>
To: Alexander Graf <agraf-l3A5Bk7waGM@public.gmane.org>
Cc: kvm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	Avi Kivity <avi-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
	kvm-ppc <kvm-ppc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	Hollis Blanchard
	<hollisb-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>,
	Arnd Bergmann <arnd-r2nGTMty4D4@public.gmane.org>,
	Kevin Wolf <kwolf-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
	bphilips-l3A5Bk7waGM@public.gmane.org,
	Marcelo Tosatti
	<mtosatti-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Subject: Re: [PATCH 17/27] Make head_64.S aware of KVM real mode code
Date: Thu, 29 Oct 2009 13:45:06 +1100	[thread overview]
Message-ID: <1256784306.26770.18.camel@pasglop> (raw)
In-Reply-To: <1256137413-15256-18-git-send-email-agraf-l3A5Bk7waGM@public.gmane.org>

On Wed, 2009-10-21 at 17:03 +0200, Alexander Graf wrote:
> We need to run some KVM trampoline code in real mode. Unfortunately, real mode
> only covers 8MB on Cell so we need to squeeze ourselves as low as possible.
> 
> Also, we need to trap interrupts to get us back from guest state to host state
> without telling Linux about it.
> 
> This patch adds interrupt traps and includes the KVM code that requires real
> mode in the real mode parts of Linux.
> 
> Signed-off-by: Alexander Graf <agraf-l3A5Bk7waGM@public.gmane.org>

Acked-by: Benjamin Herrenschmidt <benh-XVmvHMARGAS8U2dJNN8I7kB+6BGkLq7r@public.gmane.org>

> ---
>  arch/powerpc/include/asm/exception-64s.h |    2 ++
>  arch/powerpc/kernel/exceptions-64s.S     |    8 ++++++++
>  arch/powerpc/kernel/head_64.S            |    7 +++++++
>  3 files changed, 17 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/exception-64s.h b/arch/powerpc/include/asm/exception-64s.h
> index a98653b..57c4000 100644
> --- a/arch/powerpc/include/asm/exception-64s.h
> +++ b/arch/powerpc/include/asm/exception-64s.h
> @@ -147,6 +147,7 @@
>  	.globl label##_pSeries;				\
>  label##_pSeries:					\
>  	HMT_MEDIUM;					\
> +	DO_KVM	n;					\
>  	mtspr	SPRN_SPRG_SCRATCH0,r13;		/* save r13 */	\
>  	EXCEPTION_PROLOG_PSERIES(PACA_EXGEN, label##_common)
>  
> @@ -170,6 +171,7 @@ label##_pSeries:					\
>  	.globl label##_pSeries;						\
>  label##_pSeries:							\
>  	HMT_MEDIUM;							\
> +	DO_KVM	n;							\
>  	mtspr	SPRN_SPRG_SCRATCH0,r13;	/* save r13 */			\
>  	mfspr	r13,SPRN_SPRG_PACA;	/* get paca address into r13 */	\
>  	std	r9,PACA_EXGEN+EX_R9(r13);	/* save r9, r10 */	\
> diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
> index 1808876..fc3ead0 100644
> --- a/arch/powerpc/kernel/exceptions-64s.S
> +++ b/arch/powerpc/kernel/exceptions-64s.S
> @@ -41,6 +41,7 @@ __start_interrupts:
>  	. = 0x200
>  _machine_check_pSeries:
>  	HMT_MEDIUM
> +	DO_KVM	0x200
>  	mtspr	SPRN_SPRG_SCRATCH0,r13		/* save r13 */
>  	EXCEPTION_PROLOG_PSERIES(PACA_EXMC, machine_check_common)
>  
> @@ -48,6 +49,7 @@ _machine_check_pSeries:
>  	.globl data_access_pSeries
>  data_access_pSeries:
>  	HMT_MEDIUM
> +	DO_KVM	0x300
>  	mtspr	SPRN_SPRG_SCRATCH0,r13
>  BEGIN_FTR_SECTION
>  	mfspr	r13,SPRN_SPRG_PACA
> @@ -77,6 +79,7 @@ ALT_FTR_SECTION_END_IFCLR(CPU_FTR_SLB)
>  	.globl data_access_slb_pSeries
>  data_access_slb_pSeries:
>  	HMT_MEDIUM
> +	DO_KVM	0x380
>  	mtspr	SPRN_SPRG_SCRATCH0,r13
>  	mfspr	r13,SPRN_SPRG_PACA		/* get paca address into r13 */
>  	std	r3,PACA_EXSLB+EX_R3(r13)
> @@ -115,6 +118,7 @@ data_access_slb_pSeries:
>  	.globl instruction_access_slb_pSeries
>  instruction_access_slb_pSeries:
>  	HMT_MEDIUM
> +	DO_KVM	0x480
>  	mtspr	SPRN_SPRG_SCRATCH0,r13
>  	mfspr	r13,SPRN_SPRG_PACA		/* get paca address into r13 */
>  	std	r3,PACA_EXSLB+EX_R3(r13)
> @@ -154,6 +158,7 @@ instruction_access_slb_pSeries:
>  	.globl	system_call_pSeries
>  system_call_pSeries:
>  	HMT_MEDIUM
> +	DO_KVM	0xc00
>  BEGIN_FTR_SECTION
>  	cmpdi	r0,0x1ebe
>  	beq-	1f
> @@ -186,12 +191,15 @@ END_FTR_SECTION_IFSET(CPU_FTR_REAL_LE)
>  	 * trickery is thus necessary
>  	 */
>  	. = 0xf00
> +	DO_KVM	0xf00
>  	b	performance_monitor_pSeries
>  
>  	. = 0xf20
> +	DO_KVM	0xf20
>  	b	altivec_unavailable_pSeries
>  
>  	. = 0xf40
> +	DO_KVM	0xf40
>  	b	vsx_unavailable_pSeries
>  
>  #ifdef CONFIG_CBE_RAS
> diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S
> index c38afdb..9258074 100644
> --- a/arch/powerpc/kernel/head_64.S
> +++ b/arch/powerpc/kernel/head_64.S
> @@ -37,6 +37,7 @@
>  #include <asm/firmware.h>
>  #include <asm/page_64.h>
>  #include <asm/irqflags.h>
> +#include <asm/kvm_book3s_64_asm.h>
>  
>  /* The physical memory is layed out such that the secondary processor
>   * spin code sits at 0x0000...0x00ff. On server, the vectors follow
> @@ -165,6 +166,12 @@ exception_marker:
>  #include "exceptions-64s.S"
>  #endif
>  
> +/* KVM trampoline code needs to be close to the interrupt handlers */
> +
> +#ifdef CONFIG_KVM_BOOK3S_64_HANDLER
> +#include "../kvm/book3s_64_rmhandlers.S"
> +#endif
> +
>  _GLOBAL(generic_secondary_thread_init)
>  	mr	r24,r3
>