Re: [kvm-unit-tests PATCH 2/2] s390x: Remove DAT and add short indication psw bits on diag308 reset

Janosch Frank
2019-11-06T10:19:42Z

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On 11/5/19 5:28 PM, Janosch Frank wrote:
> On a diag308 subcode 0 CRs will be reset, so we need to mask of PSW
> DAT indication until we restore our CRs.
>
> Also we need to set the short psw indication to be compliant with the
> architecture.
>
> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
> ---
> lib/s390x/asm-offsets.c | 1 +
> lib/s390x/asm/arch_def.h | 3 ++-
> s390x/cstart64.S | 20 ++++++++++++++------
> 3 files changed, 17 insertions(+), 7 deletions(-)
>
> diff --git a/lib/s390x/asm-offsets.c b/lib/s390x/asm-offsets.c
> index 4b213f8..61d2658 100644
> --- a/lib/s390x/asm-offsets.c
> +++ b/lib/s390x/asm-offsets.c
> @@ -58,6 +58,7 @@ int main(void)
> OFFSET(GEN_LC_SW_INT_FPRS, lowcore, sw_int_fprs);
> OFFSET(GEN_LC_SW_INT_FPC, lowcore, sw_int_fpc);
> OFFSET(GEN_LC_SW_INT_CRS, lowcore, sw_int_crs);
> + OFFSET(GEN_LC_SW_INT_PSW, lowcore, sw_int_psw);
> OFFSET(GEN_LC_MCCK_EXT_SA_ADDR, lowcore, mcck_ext_sa_addr);
> OFFSET(GEN_LC_FPRS_SA, lowcore, fprs_sa);
> OFFSET(GEN_LC_GRS_SA, lowcore, grs_sa);
> diff --git a/lib/s390x/asm/arch_def.h b/lib/s390x/asm/arch_def.h
> index 07d4e5e..7d25e4f 100644
> --- a/lib/s390x/asm/arch_def.h
> +++ b/lib/s390x/asm/arch_def.h
> @@ -79,7 +79,8 @@ struct lowcore {
> uint32_t sw_int_fpc; /* 0x0300 */
> uint8_t pad_0x0304[0x0308 - 0x0304]; /* 0x0304 */
> uint64_t sw_int_crs[16]; /* 0x0308 */
> - uint8_t pad_0x0310[0x11b0 - 0x0388]; /* 0x0388 */
> + struct psw sw_int_psw; /* 0x0388 */
> + uint8_t pad_0x0310[0x11b0 - 0x0390]; /* 0x0390 */

That's obviously not correct, the psw is two DWORDS long, not one...

> uint64_t mcck_ext_sa_addr; /* 0x11b0 */
> uint8_t pad_0x11b8[0x1200 - 0x11b8]; /* 0x11b8 */
> uint64_t fprs_sa[16]; /* 0x1200 */
> diff --git a/s390x/cstart64.S b/s390x/cstart64.S
> index 0455591..2e0dcf5 100644
> --- a/s390x/cstart64.S
> +++ b/s390x/cstart64.S
> @@ -129,8 +129,15 @@ memsetxc:
> .globl diag308_load_reset
> diag308_load_reset:
> SAVE_REGS
> - /* Save the first PSW word to the IPL PSW */
> + /* Backup current PSW */
> epsw %r0, %r1
> + st %r0, GEN_LC_SW_INT_PSW
> + st %r1, GEN_LC_SW_INT_PSW + 4
> + /* Disable DAT as the CRs will be reset too */
> + nilh %r0, 0xfbff
> + /* Add psw bit 12 to indicate short psw */
> + oilh %r0, 0x0008
> + /* Save the first PSW word to the IPL PSW */
> st %r0, 0
> /* Store the address and the bit for 31 bit addressing */
> larl %r0, 0f
> @@ -142,12 +149,13 @@ diag308_load_reset:
> xgr %r2, %r2
> br %r14
> /* Success path */
> - /* We lost cr0 due to the reset */
> -0: larl %r1, initial_cr0
> - lctlg %c0, %c0, 0(%r1)
> - RESTORE_REGS
> + /* Switch to z/Architecture mode and 64-bit */
> +0: RESTORE_REGS
> lhi %r2, 1
> - br %r14
> + larl %r0, 1f
> + stg %r0, GEN_LC_SW_INT_PSW + 8
> + lpswe GEN_LC_SW_INT_PSW
> +1: br %r14
>
> .globl smp_cpu_setup_state
> smp_cpu_setup_state:
>

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