On 09/10/19 12:35, Thomas Huth wrote:
> On 04/10/2019 12.38, David Gibson wrote:
>> In order to call RTAS functions on powerpc kvm-unit-tests relies on the
>> RTAS blob supplied by qemu. But new versions of qemu don't supply an RTAS
>> blob: since the normal way for guests to get RTAS is to call the guest
>> firmware's instantiate-rtas function, we now rely on that guest firmware
>> to provide the RTAS code itself.
>>
>> But qemu-kvm-tests bypasses the usual guest firmware to just run itself,
>
> s/qemu-kvm-tests/kvm-unit-tests/
>
>> so we can't get the rtas blob from SLOF.
>>
>> But.. in fact the RTAS blob under qemu is a bit of a sham anyway - it's
>> a tiny wrapper that forwards the RTAS call to a hypercall. So, we can
>> just invoke that hypercall directly.
>>
>> Signed-off-by: David Gibson <david@xxxxxxxxxxxxxxxxxxxxx>
>> ---
>> lib/powerpc/asm/hcall.h | 3 +++
>> lib/powerpc/rtas.c | 6 +++---
>> powerpc/cstart64.S | 20 ++++++++++++++++----
>> 3 files changed, 22 insertions(+), 7 deletions(-)
>>
>> So.. "new versions of qemu" in this case means ones that incorporate
>> the pull request I just sent today.
>>
>> diff --git a/lib/powerpc/asm/hcall.h b/lib/powerpc/asm/hcall.h
>> index a8bd7e3..1173fea 100644
>> --- a/lib/powerpc/asm/hcall.h
>> +++ b/lib/powerpc/asm/hcall.h
>> @@ -24,6 +24,9 @@
>> #define H_RANDOM 0x300
>> #define H_SET_MODE 0x31C
>>
>> +#define KVMPPC_HCALL_BASE 0xf000
>> +#define KVMPPC_H_RTAS (KVMPPC_HCALL_BASE + 0x0)
>> +
>> #ifndef __ASSEMBLY__
>> /*
>> * hcall_have_broken_sc1 checks if we're on a host with a broken sc1.
>> diff --git a/lib/powerpc/rtas.c b/lib/powerpc/rtas.c
>> index 2e7e0da..41c0a24 100644
>> --- a/lib/powerpc/rtas.c
>> +++ b/lib/powerpc/rtas.c
>> @@ -46,9 +46,9 @@ void rtas_init(void)
>> prop = fdt_get_property(dt_fdt(), node,
>> "linux,rtas-entry", &len);
>> if (!prop) {
>> - printf("%s: /rtas/linux,rtas-entry: %s\n",
>> - __func__, fdt_strerror(len));
>> - abort();
>> + /* We don't have a qemu provided RTAS blob, enter_rtas
>> + * will use H_RTAS directly */
>> + return;
>> }
>> data = (u32 *)prop->data;
>> rtas_entry = (unsigned long)fdt32_to_cpu(*data);
>> diff --git a/powerpc/cstart64.S b/powerpc/cstart64.S
>> index ec673b3..972851f 100644
>> --- a/powerpc/cstart64.S
>> +++ b/powerpc/cstart64.S
>> @@ -121,13 +121,25 @@ halt:
>>
>> .globl enter_rtas
>> enter_rtas:
>> + LOAD_REG_ADDR(r11, rtas_entry)
>> + ld r10, 0(r11)
>> +
>> + cmpdi r10,0
>> + bne external_rtas
>> +
>> + /* Use H_RTAS directly */
>> + mr r4,r3
>> + lis r3,KVMPPC_H_RTAS@h
>> + ori r3,r3,KVMPPC_H_RTAS@l
>> + b hcall
>> +
>> +external_rtas:
>> + /* Use external RTAS blob */
>> mflr r0
>> std r0, 16(r1)
>>
>> - LOAD_REG_ADDR(r10, rtas_return_loc)
>> - mtlr r10
>> - LOAD_REG_ADDR(r11, rtas_entry)
>> - ld r10, 0(r11)
>> + LOAD_REG_ADDR(r11, rtas_return_loc)
>> + mtlr r11
>>
>> mfmsr r11
>> LOAD_REG_IMMEDIATE(r9, RTAS_MSR_MASK)
>>
>
> With the typo in the commit message fixed:
> Reviewed-by: Thomas Huth <thuth@xxxxxxxxxx>
>
> Paolo, I currently don't have any other kvm-unit-test patches pending,
> could you pick this up directly, please?
Ok, thanks.
Paolo
