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

Benjamin Herrenschmidt
2009-10-29T02:45:06Z

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
>