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powerpc/xive: add XIVE Exploitation Mode to CAS

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On POWER9, the Client Architecture Support (CAS) negotiation process
determines whether the guest operates in XIVE Legacy compatibility or
in XIVE exploitation mode. Now that we have initial guest support for
the XIVE interrupt controller, let's inform the hypervisor what we can
do.

The platform advertises the XIVE Exploitation Mode support using the
property "ibm,arch-vec-5-platform-support-vec-5", byte 23 bits 0-1 :

 - 0b00 XIVE legacy mode Only
 - 0b01 XIVE exploitation mode Only
 - 0b10 XIVE legacy or exploitation mode

The OS asks for XIVE Exploitation Mode support using the property
"ibm,architecture-vec-5", byte 23 bits 0-1:

 - 0b00 XIVE legacy mode Only
 - 0b01 XIVE exploitation mode Only

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Cédric Le Goater
2017-08-30 21:46:16 +02:00
committed by Michael Ellerman
parent bed81ee181
commit ac5e5a5402
2 changed files with 37 additions and 2 deletions
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34
arch/powerpc/kernel/prom_init.c
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@@ -177,6 +177,7 @@ struct platform_support {
bool hash_mmu;
bool radix_mmu;
bool radix_gtse;
bool xive;
};
/* Platforms codes are now obsolete in the kernel. Now only used within this
@@ -1041,6 +1042,27 @@ static void __init prom_parse_mmu_model(u8 val,
}
}
static void __init prom_parse_xive_model(u8 val,
struct platform_support *support)
{
switch (val) {
case OV5_FEAT(OV5_XIVE_EITHER): /* Either Available */
prom_debug("XIVE - either mode supported\n");
support->xive = true;
break;
case OV5_FEAT(OV5_XIVE_EXPLOIT): /* Only Exploitation mode */
prom_debug("XIVE - exploitation mode supported\n");
support->xive = true;
break;
case OV5_FEAT(OV5_XIVE_LEGACY): /* Only Legacy mode */
prom_debug("XIVE - legacy mode supported\n");
break;
default:
prom_debug("Unknown xive support option: 0x%x\n", val);
break;
}
}
static void __init prom_parse_platform_support(u8 index, u8 val,
struct platform_support *support)
{
@@ -1054,6 +1076,10 @@ static void __init prom_parse_platform_support(u8 index, u8 val,
support->radix_gtse = true;
}
break;
case OV5_INDX(OV5_XIVE_SUPPORT): /* Interrupt mode */
prom_parse_xive_model(val & OV5_FEAT(OV5_XIVE_SUPPORT),
support);
break;
}
}
@@ -1062,7 +1088,8 @@ static void __init prom_check_platform_support(void)
struct platform_support supported = {
.hash_mmu = false,
.radix_mmu = false,
.radix_gtse = false
.radix_gtse = false,
.xive = false
};
int prop_len = prom_getproplen(prom.chosen,
"ibm,arch-vec-5-platform-support");
@@ -1095,6 +1122,11 @@ static void __init prom_check_platform_support(void)
/* We're probably on a legacy hypervisor */
prom_debug("Assuming legacy hash support\n");
}
if (supported.xive) {
prom_debug("Asking for XIVE\n");
ibm_architecture_vec.vec5.intarch = OV5_FEAT(OV5_XIVE_EXPLOIT);
}
}
static void __init prom_send_capabilities(void)