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feat(ssnpm): Add support for pointer masking #354

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f92160a
update(riscv): add missing henvcfg field definitions
ninolomata Apr 9, 2026
48cbcea
feat(riscv): add Ssnpm PMM configuration support
ninolomata Apr 9, 2026
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14 changes: 14 additions & 0 deletions src/arch/riscv/inc/arch/csrs.h
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Original file line number Diff line number Diff line change
Expand Up @@ -230,6 +230,9 @@
#define HSTATUS_VSXL_OFF (32)
#define HSTATUS_VSXL_LEN (2)
#define HSTATUS_VSXL_MSK (BIT_MASK(HSTATUS_VSXL_OFF, HSTATUS_VSXL_LEN))
#define HSTATUS_HUPMM_OFF (48)
#define HSTATUS_HUPMM_LEN (2)
#define HSTATUS_HUPMM_MSK (BIT_MASK(HSTATUS_HUPMM_OFF, HSTATUS_HUPMM_LEN))
#if defined(RV64)
#define HSTATUS_VSXL_32 (1UL << HSTATUS_VSXL_OFF)
#define HSTATUS_VSXL_64 (2UL << HSTATUS_VSXL_OFF)
Expand All @@ -243,16 +246,27 @@
#endif

#define HENVCFG_FIOM (1ULL << 0)
#define HENVCFG_LPE (1ULL << 2)
#define HENVCFG_SSE (1ULL << 3)
#define HENVCFG_CBIE_OFF (4)
#define HENVCFG_CBIE_LEN (2)
#define HENVCFG_CBIE_MSK (BIT_MASK(HENVCFG_CBIE_OFF, HENVCFG_CBIE_LEN))
#define HENVCFG_CBCFE (1ULL << 6)
#define HENVCFG_CBZE (1ULL << 7)
#define HENVCFG_PMM_OFF (32)
#define HENVCFG_PMM_LEN (2)
#define HENVCFG_PMM_MSK (BIT_MASK(HENVCFG_PMM_OFF, HENVCFG_PMM_LEN))
#define HENVCFG_DTE (1ULL << 59)
#define HENVCFG_ADUE (1ULL << 61)
#define HENVCFG_PBMTE (1ULL << 62)
#define HENVCFG_STCE (1ULL << 63)

#define HENVCFG_CBIE_FLUSH (1ULL << HENVCFG_CBIE_OFF)
#define HENVCFG_CBIE_INV (3ULL << HENVCFG_CBIE_OFF)
#define HENVCFG_PMM_DISABLED (0ULL)
#define HENVCFG_PMM_REV (1ULL)
#define HENVCFG_PMM_PMLEN_7 (2ULL)
#define HENVCFG_PMM_PMLEN_16 (3ULL)

#define HSTATEEN_C (1ULL << 0)
#define HSTATEEN_FCSR (1ULL << 1)
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40 changes: 40 additions & 0 deletions src/arch/riscv/vmm.c
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Expand Up @@ -81,6 +81,46 @@ void vmm_arch_init()
}
}

#if CPU_HAS_EXTENSION(CPU_EXT_SSNPM)
#if defined(RV32)
#error "Ssnpm extension is not available for RV32. Please disable CPU_EXT_SSNPM."
#elif !defined(CPU_EXT_SSNPM_PMM_MODE)
#error "Ssnpm extension PMM mode is not defined. Please define CPU_EXT_SSNPM_PMM_MODE."
#else

@josecm josecm Sep 4, 2026

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I don't think these checks should be here. What I'd suggest is to have a private function vmm_arch_config_ssmpm and then an if (CPU_HAS_EXT(...)) vmm_arch_config_ssmpm().

/**
* Program the guest-visible Ssnpm PMM mode if the hypervisor was
* configured to use it (via the CPU_EXT_SSNPM_PMM_MODE macro).
* Otherwise, henvcfg keeps the reset value written above.
*/
uint64_t pmm_val = 0;

switch (CPU_EXT_SSNPM_PMM_MODE) {
case HENVCFG_PMM_DISABLED:
if (cpu_is_master()) {
WARNING("Ssnpm extension is enabled but PMM mode is set to disabled.\r\n");

@josecm josecm Sep 4, 2026

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Should actually be "extension is present". But I don't believe this is worth it. I don't think we should allow the configruation in this way. Either we: (i) simply disable support for the extension for now, or (ii) allow to set this in the config in a config global .arch field (i believe we have to add this) (e.g., .arch.npm_mode) or (ii) allow to set the mode per vm, in the a vm config arch field (e.g., arch.npm_mode field)

}
pmm_val = HENVCFG_PMM_DISABLED << HENVCFG_PMM_OFF;
break;
case HENVCFG_PMM_PMLEN_7:
pmm_val = HENVCFG_PMM_PMLEN_7 << HENVCFG_PMM_OFF;
break;
case HENVCFG_PMM_PMLEN_16:
pmm_val = HENVCFG_PMM_PMLEN_16 << HENVCFG_PMM_OFF;
break;
default:
if (cpu_is_master()) {
ERROR("Unsupported PMM mode for Ssnpm extension.\r\n");
}
}

csrs_henvcfg_set(pmm_val);

@josecm josecm Sep 4, 2026

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To make sure we do this cleanly dont we first need to csrs_henvcfg_clear(HENVCFG_PMM_MSK) ?

bool ssnpm_present = ((csrs_henvcfg_read() & pmm_val) == pmm_val);
if (cpu_is_master() && !ssnpm_present) {
ERROR("Platform configured to use Ssnpm extension, but extension not present.\r\n");
}
#endif
#endif

/**
* Configure the State Enable mechanism (Ssstateen).
*
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2 changes: 2 additions & 0 deletions src/platform/qemu-riscv64-virt/inc/plat/cpu_ext.h
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Original file line number Diff line number Diff line change
Expand Up @@ -10,5 +10,7 @@
#if !defined(RV32)
#define CPU_EXT_SVPBMT 1
#endif
#define CPU_EXT_SSNPM 0
#define CPU_EXT_SSNPM_PMM_MODE HENVCFG_PMM_DISABLED

#endif
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