Re: [kvm-unit-tests PATCH v2 5/6] s390x: Use interrupts in SCLP

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

 



On 05.12.18 16:39, Janosch Frank wrote:
> We need to properly implement interrupt handling for SCLP, because on
> z/VM and LPAR SCLP calls are not synchronous!
> 
> Signed-off-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
> ---
>  lib/s390x/asm/arch_def.h  |  1 +
>  lib/s390x/asm/interrupt.h |  2 ++
>  lib/s390x/interrupt.c     | 12 ++++++++++--
>  lib/s390x/io.c            |  2 +-
>  lib/s390x/sclp-console.c  | 29 +++++++++--------------------
>  lib/s390x/sclp.c          | 42 ++++++++++++++++++++++++++++++++++++++++++
>  lib/s390x/sclp.h          |  4 +++-
>  7 files changed, 68 insertions(+), 24 deletions(-)
> 
> diff --git a/lib/s390x/asm/arch_def.h b/lib/s390x/asm/arch_def.h
> index d2d6e02..27c6b85 100644
> --- a/lib/s390x/asm/arch_def.h
> +++ b/lib/s390x/asm/arch_def.h
> @@ -33,6 +33,7 @@ struct psw {
>  	uint64_t	addr;
>  };
>  
> +#define PSW_MASK_EXT			0x0100000000000000UL
>  #define PSW_MASK_DAT			0x0400000000000000UL
>  #define PSW_MASK_PSTATE			0x0001000000000000UL
>  
> diff --git a/lib/s390x/asm/interrupt.h b/lib/s390x/asm/interrupt.h
> index 013709f..de15d9e 100644
> --- a/lib/s390x/asm/interrupt.h
> +++ b/lib/s390x/asm/interrupt.h
> @@ -11,6 +11,8 @@
>  #define _ASMS390X_IRQ_H_
>  #include <asm/arch_def.h>
>  
> +#define EXT_IRQ_SERVICE_SIG 0x2401
> +
>  void handle_pgm_int(void);
>  void handle_ext_int(void);
>  void handle_mcck_int(void);
> diff --git a/lib/s390x/interrupt.c b/lib/s390x/interrupt.c
> index cf0a794..7118577 100644
> --- a/lib/s390x/interrupt.c
> +++ b/lib/s390x/interrupt.c
> @@ -12,6 +12,7 @@
>  #include <libcflat.h>
>  #include <asm/interrupt.h>
>  #include <asm/barrier.h>
> +#include <sclp.h>
>  
>  static bool pgm_int_expected;
>  static struct lowcore *lc;
> @@ -107,8 +108,15 @@ void handle_pgm_int(void)
>  
>  void handle_ext_int(void)
>  {
> -	report_abort("Unexpected external call interrupt: at %#lx",
> -		     lc->ext_old_psw.addr);
> +	if (lc->ext_int_code != EXT_IRQ_SERVICE_SIG)
> +		report_abort("Unexpected external call interrupt: at %#lx",
> +			     lc->ext_old_psw.addr);
> +	else {
> +		lc->ext_old_psw.mask &= ~PSW_MASK_EXT;
> +		lc->sw_int_cr0 &= ~(1UL << 9);
> +		sclp_handle_ext();
> +		lc->ext_int_code = 0;
> +	}
>  }
>  
>  void handle_mcck_int(void)
> diff --git a/lib/s390x/io.c b/lib/s390x/io.c
> index 05a0765..7294165 100644
> --- a/lib/s390x/io.c
> +++ b/lib/s390x/io.c
> @@ -45,8 +45,8 @@ void setup(void)
>  {
>  	setup_args_progname(ipl_args);
>  	setup_facilities();
> -	sclp_console_setup();
>  	sclp_memory_setup();
> +	sclp_console_setup();
>  }
>  
>  void exit(int code)
> diff --git a/lib/s390x/sclp-console.c b/lib/s390x/sclp-console.c
> index deacbde..13ab03d 100644
> --- a/lib/s390x/sclp-console.c
> +++ b/lib/s390x/sclp-console.c
> @@ -13,30 +13,13 @@
>  #include <asm/page.h>
>  #include "sclp.h"
>  
> -char _sccb[PAGE_SIZE] __attribute__((__aligned__(4096)));
> -
> -/* Perform service call. Return 0 on success, non-zero otherwise. */
> -int sclp_service_call(unsigned int command, void *sccb)
> -{
> -        int cc;
> -
> -        asm volatile(
> -                "       .insn   rre,0xb2200000,%1,%2\n"  /* servc %1,%2 */
> -                "       ipm     %0\n"
> -                "       srl     %0,28"
> -                : "=&d" (cc) : "d" (command), "a" (__pa(sccb))
> -                : "cc", "memory");
> -        if (cc == 3)
> -                return -1;
> -        if (cc == 2)
> -                return -1;
> -        return 0;
> -}
> -
>  static void sclp_set_write_mask(void)
>  {
>  	WriteEventMask *sccb = (void *)_sccb;
>  
> +	while (sclp_busy)
> +		/* Wait for SCLP request to complete */;

should we use barrier(); here to make this clearer?

> +	sclp_busy = true;
>  	sccb->h.length = sizeof(WriteEventMask);
>  	sccb->mask_length = sizeof(unsigned int);
>  	sccb->receive_mask = SCLP_EVENT_MASK_MSG_ASCII;
> @@ -57,6 +40,9 @@ void sclp_print(const char *str)
>  	int len = strlen(str);
>  	WriteEventData *sccb = (void *)_sccb;
>  
> +	while (sclp_busy)
> +		/* Wait for SCLP request to complete */;

dito

(I guess do not we need barriers between setting sclp_busy and testing
it, because we're using volatile and we don't have multi-threading
messing with the value)

> +	sclp_busy = true;
>  	sccb->h.length = sizeof(WriteEventData) + len;
>  	sccb->h.function_code = SCLP_FC_NORMAL_WRITE;
>  	sccb->ebh.length = sizeof(EventBufferHeader) + len;
> @@ -65,4 +51,7 @@ void sclp_print(const char *str)
>  	memcpy(sccb->data, str, len);
>  
>  	sclp_service_call(SCLP_CMD_WRITE_EVENT_DATA, sccb);
> +	while (sclp_busy)
> +		/* Wait for SCLP request to complete */;

dito

> +
>  }
> diff --git a/lib/s390x/sclp.c b/lib/s390x/sclp.c
> index 1d4a010..cd0e5e5 100644
> --- a/lib/s390x/sclp.c
> +++ b/lib/s390x/sclp.c
> @@ -23,6 +23,9 @@ static uint64_t storage_increment_size;
>  static uint64_t max_ram_size;
>  static uint64_t ram_size;
>  
> +char _sccb[PAGE_SIZE] __attribute__((__aligned__(4096)));
> +volatile bool sclp_busy = false;

false should be the default value already.

> +
>  static void mem_init(phys_addr_t mem_end)
>  {
>  	phys_addr_t freemem_start = (phys_addr_t)&stacktop;
> @@ -30,6 +33,42 @@ static void mem_init(phys_addr_t mem_end)
>  	phys_alloc_init(freemem_start, mem_end - freemem_start);
>  }
>  
> +static void sclp_setup_int(void)
> +{
> +	uint64_t mask;
> +
> +	ctl_set_bit(0, 9);
> +
> +	mask = extract_psw_mask();
> +	mask |= PSW_MASK_EXT;
> +	load_psw_mask(mask);
> +}
> +
> +void sclp_handle_ext(void)
> +{

Error out if !sclp_busy but we get an interrupt?

> +	ctl_clear_bit(0, 9);
> +	sclp_busy = false;
> +}
> +
> +/* Perform service call. Return 0 on success, non-zero otherwise. */
> +int sclp_service_call(unsigned int command, void *sccb)
> +{
> +        int cc;
> +
> +	sclp_setup_int();
> +        asm volatile(
> +                "       .insn   rre,0xb2200000,%1,%2\n"  /* servc %1,%2 */
> +                "       ipm     %0\n"
> +                "       srl     %0,28"
> +                : "=&d" (cc) : "d" (command), "a" (__pa(sccb))
> +                : "cc", "memory");
> +        if (cc == 3)
> +                return -1;
> +        if (cc == 2)
> +                return -1;
> +        return 0;
> +}

Guess moving that (including _sccb) could also be a separate patch ;)

> +
>  void sclp_memory_setup(void)
>  {
>  	ReadInfo *ri = (void *)_sccb;
> @@ -37,7 +76,10 @@ void sclp_memory_setup(void)
>  	int cc;
>  
>  	ri->h.length = SCCB_SIZE;
> +	sclp_busy = true;
>  	sclp_service_call(SCLP_CMDW_READ_SCP_INFO_FORCED, ri);
> +	while (sclp_busy)
> +		/* Wait for SCLP request to complete */;

Should we factor that out into something like

sclp_start_request()
{
	sclp_busy = true;
}

sclp_wait_response()
{
	while (sclp_busy)
		barrier();
}

>  
>  	/* calculate the storage increment size */
>  	rnsize = ri->rnsize;
> diff --git a/lib/s390x/sclp.h b/lib/s390x/sclp.h
> index e008932..a91aad1 100644
> --- a/lib/s390x/sclp.h
> +++ b/lib/s390x/sclp.h
> @@ -207,9 +207,11 @@ typedef struct ReadEventData {
>      uint32_t mask;
>  } __attribute__((packed)) ReadEventData;
>  
> +extern char _sccb[];
> +volatile bool sclp_busy;
> +void sclp_handle_ext(void);
>  void sclp_console_setup(void);
>  void sclp_print(const char *str);
> -extern char _sccb[];
>  int sclp_service_call(unsigned int command, void *sccb);
>  void sclp_memory_setup(void);
>  
> 


-- 

Thanks,

David / dhildenb



[Index of Archives]     [KVM ARM]     [KVM ia64]     [KVM ppc]     [Virtualization Tools]     [Spice Development]     [Libvirt]     [Libvirt Users]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite Questions]     [Linux Kernel]     [Linux SCSI]     [XFree86]

  Powered by Linux