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v1: https://lore.kernel.org/qemu-devel/20260507040153.14565-1-matthew@pq.io/ Changes in v2 (all in patch 2/2, applesmc_isa_realize() #KEY block): * Add braces around the QLIST_FOREACH() count loop body (qemu coding style: loops always need braces, even single-line). Reported-by: Peter Maydell <peter.maydell@linaro.org> * Replace the manual 4-byte big-endian byte-shift packing of `count` into `numkey_buf` with a single stl_be_p() call. Reported-by: Peter Maydell <peter.maydell@linaro.org> Patch 1/2 is unchanged from v1. Peter also noted that the static-buffer "must remain valid forever" contract that applesmc_add_key() requires is awkward — fair, but fixing it (e.g. switching the key table to a glib hashtable that copies values) is independent from this series and not reported as performance-noticeable in profiles. Happy to follow up with a hashtable conversion as a separate series if the maintainers think it's worth doing. Original v1 cover letter follows below. --- The QEMU applesmc device implements just enough of the Apple SMC PMIO protocol to satisfy the OSK boot check on older macOS versions. On modern macOS guests (x86 10.14+, all of the 15.x series) the real AppleSMC kext enumerates the SMC key space at boot via APPLESMC_GET_KEY_BY_INDEX_CMD (0x12). The current device only acknowledges APPLESMC_READ_CMD (0x10) at the command port; every other command falls through to the default arm of the switch and sets ST_1E_BAD_CMD. The macOS driver interprets the resulting 0x82 reply as "spurious data" and enters a retry loop that floods the kernel log with kSMCSpuriousData (0x81) / kSMCKeyNotFound errors at roughly 1800 events per second, pegging kernel_task at ~70% CPU and WindowServer at ~509% CPU. This reproduces reliably on any recent macOS 15 guest booted with -device isa-applesmc,osk=<valid-OSK>. This two-patch series fixes the protocol-level bug and rounds out the SMC key table to a complete iMac20,1 profile. Patch 1: protocol-level fix - Accept WRITE_CMD, GET_KEY_BY_INDEX_CMD, GET_KEY_TYPE_CMD at the command port (in addition to READ_CMD). - Implement the indexed-iteration walker (returns real key names from s->data_def, or APPLESMC_ST_1E_BAD_INDEX 0xb8 once the index is past the end so the guest stops iterating). - Implement GET_KEY_TYPE returning a 6-byte type/size/attr response matching VirtualSMC's kern_pmio.cpp behaviour. - Accept and log WRITE_CMD silently. - Replace the unknown-key NOEXIST (0x84) reply with a zeroed payload of the requested length, logged at LOG_UNIMP. - Route the BAD_CMD path through qemu_log_mask(LOG_GUEST_ERROR). - Fix MSSD initialiser typo ("\0x3" -> "\x03"). The original literal was three bytes ('\0', 'x', '3') truncated to one ('\0') by the size argument, so MSSD has been silently returning 0 since the device was introduced; the corrected value matches what a real iMac20,1 SMC reports. Patch 2: populate the key table - Add 94 keys covering the categories macOS queries on a Sequoia 15.7.5 guest: 28 temperature sensors (sp78), 4 fan keys (fpe2), 12 power-rail keys, 6 DIMM keys, 11 SMC-internal bookkeeping, 13 motion-sensor / wireless, 3 write targets (HE0N/MSDW/NTOK), 2 power-management gates (HE2N/WDTC), 8 platform-identity / probe keys, plus the Apple-canonical #KEY total-count. - Sensor values match a real iMac20,1 idle probe published at https://linux-hardware.org/?probe=999fc708a4&log=sensors: CPU 40-51 C, GPU 36-42 C, fan at 1200 RPM (= F0Mn idle), etc. Measured impact (macOS 15.7.5 guest, iMac20,1 profile): Metric | Before | After -----------------|---------:|------: SMC errors / 5s | 9,225 | 2 kernel_task CPU | 70 % | ~2 % WindowServer CPU | 509 % | ~6 % A note for review on the zero-valued keys in patch 2: the 26 keys covering DIMM / SMC bookkeeping / motion-sensor / wireless rails are registered with present-with-zero values rather than omitted. macOS distinguishes "absent" (NOEXIST reply, retry-poll) from "broken" (present, value 0, accepted-and-ignored). Registering these keys present-with-zero stops the retry-poll behaviour without asserting any specific value. If the maintainer prefers a tighter scope for this series I am happy to drop any subset and follow up; the present-with-zero approach was driven by which keys macOS observed querying during boot. Backwards compatibility: legacy macOS guests (10.11-10.13) which do not iterate the key space via GET_KEY_BY_INDEX boot unchanged. The original six keys (REV/OSK0/OSK1/NATJ/MSSP/MSSD) are still present and respond with the same values, modulo the MSSD typo fix in patch 1 which corrects MSSD to the value a real iMac20,1 SMC reports. Tested against current master (post v11.0.0). Builds clean on gcc-13 / clang-17 with --enable-werror. Sequoia 15.7.5 guest boots to login screen with the SMC retry storm absent from the kernel log; smoke test recipe in TESTING.md alongside the series. Matthew Jackson (2): hw/misc/applesmc: fix GET_KEY_BY_INDEX to return real keys, accept WRITE/TYPE commands hw/misc/applesmc: populate Apple SMC key table hw/misc/applesmc.c | 346 +++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 338 insertions(+), 8 deletions(-) -- 2.50.1 (Apple Git-155)
v1: https://lore.kernel.org/qemu-devel/20260507040153.14565-1-matthew@pq.io/ v2: https://lore.kernel.org/qemu-devel/20260507152030.48753-1-matthew@pq.io/ This is a rebase/respin of v2, which had no outstanding review comments after Peter's two style nits were addressed. Resending on current master with checkpatch cleared, plus a new patch 3/3 that gives the file a MAINTAINERS entry. Changes in v3: * New patch 3/3: add a MAINTAINERS entry for hw/misc/applesmc.c. The file currently has no entry, so get_maintainer.pl resolves only the open list and these patches had no designated reviewer. This is easy to drop if a maintainer would rather route it elsewhere; patches 1-2 do not depend on it. * Rebased on current master. hw/misc/applesmc.c is byte-identical upstream to the v2 base (blob fd96f5f), so the rebase is a clean no-op with no functional change to patches 1-2 from v2. * checkpatch cleanups in patches 1-2, no functional change: - patch 1/2: reformat the GET_KEY_TYPE 4th-byte block comment to the leading-/* and trailing-*/-on-their-own-line house style. - patch 2/2: shorten the F0Ac fan-key comment to stay under the 80-column limit. Both were pre-existing checkpatch warnings; neither was raised in the v1/v2 review. The series is now checkpatch-clean. Changes in v2 (carried into v3, all in patch 2/2, #KEY block): * Add braces around the QLIST_FOREACH() count loop body (qemu coding style: loops always need braces, even single-line). Reported-by: Peter Maydell <peter.maydell@linaro.org> * Replace the manual 4-byte big-endian byte-shift packing of `count` into `numkey_buf` with a single stl_be_p() call. Reported-by: Peter Maydell <peter.maydell@linaro.org> Patch 1/2 is otherwise unchanged since v1. On Peter's v2 remark that applesmc_add_key()'s "pointer must remain valid forever" contract is awkward: agreed it's not ideal, but the fix (e.g. converting the key table to a glib hashtable that copies values) is orthogonal to this protocol bug fix and isn't reported as noticeable in profiles. Happy to send that conversion as a separate follow-up series if the maintainers think it's worth doing. Original v1 cover letter follows below. --- The QEMU applesmc device implements just enough of the Apple SMC PMIO protocol to satisfy the OSK boot check on older macOS versions. On modern macOS guests (x86 10.14+, all of the 15.x series) the real AppleSMC kext enumerates the SMC key space at boot via APPLESMC_GET_KEY_BY_INDEX_CMD (0x12). The current device only acknowledges APPLESMC_READ_CMD (0x10) at the command port; every other command falls through to the default arm of the switch and sets ST_1E_BAD_CMD. The macOS driver interprets the resulting 0x82 reply as "spurious data" and enters a retry loop that floods the kernel log with kSMCSpuriousData (0x81) / kSMCKeyNotFound errors at roughly 1800 events per second, pegging kernel_task at ~70% CPU and WindowServer at ~509% CPU. This reproduces reliably on any recent macOS 15 guest booted with -device isa-applesmc,osk=<valid-OSK>. This series fixes the protocol-level bug and rounds out the SMC key table to a complete iMac20,1 profile. Patch 1: protocol-level fix - Accept WRITE_CMD, GET_KEY_BY_INDEX_CMD, GET_KEY_TYPE_CMD at the command port (in addition to READ_CMD). - Implement the indexed-iteration walker (returns real key names from s->data_def, or APPLESMC_ST_1E_BAD_INDEX 0xb8 once the index is past the end so the guest stops iterating). - Implement GET_KEY_TYPE returning a 6-byte type/size/attr response matching VirtualSMC's kern_pmio.cpp behaviour. - Accept and log WRITE_CMD silently. - Replace the unknown-key NOEXIST (0x84) reply with a zeroed payload of the requested length, logged at LOG_UNIMP. - Route the BAD_CMD path through qemu_log_mask(LOG_GUEST_ERROR). - Fix MSSD initialiser typo ("\0x3" -> "\x03"). The original literal was three bytes ('\0', 'x', '3') truncated to one ('\0') by the size argument, so MSSD has been silently returning 0 since the device was introduced; the corrected value matches what a real iMac20,1 SMC reports. Patch 2: populate the key table - Add 94 keys covering the categories macOS queries on a Sequoia 15.7.5 guest: 28 temperature sensors (sp78), 4 fan keys (fpe2), 12 power-rail keys, 6 DIMM keys, 11 SMC-internal bookkeeping, 13 motion-sensor / wireless, 3 write targets (HE0N/MSDW/NTOK), 2 power-management gates (HE2N/WDTC), 8 platform-identity / probe keys, plus the Apple-canonical #KEY total-count. - Sensor values match a real iMac20,1 idle probe published at https://linux-hardware.org/?probe=999fc708a4&log=sensors: CPU 40-51 C, GPU 36-42 C, fan at 1200 RPM (= F0Mn idle), etc. Patch 3: MAINTAINERS entry for the device (see "Changes in v3"). Measured impact (macOS 15.7.5 guest, iMac20,1 profile): Metric | Before | After -----------------|---------:|------: SMC errors / 5s | 9,225 | 2 kernel_task CPU | 70 % | ~2 % WindowServer CPU | 509 % | ~6 % A note for review on the zero-valued keys in patch 2: the 26 keys covering DIMM / SMC bookkeeping / motion-sensor / wireless rails are registered with present-with-zero values rather than omitted. macOS distinguishes "absent" (NOEXIST reply, retry-poll) from "broken" (present, value 0, accepted-and-ignored). Registering these keys present-with-zero stops the retry-poll behaviour without asserting any specific value. If the maintainer prefers a tighter scope for this series I am happy to drop any subset and follow up; the present-with-zero approach was driven by which keys macOS observed querying during boot. Backwards compatibility: legacy macOS guests (10.11-10.13) which do not iterate the key space via GET_KEY_BY_INDEX boot unchanged. The original six keys (REV/OSK0/OSK1/NATJ/MSSP/MSSD) are still present and respond with the same values, modulo the MSSD typo fix in patch 1 which corrects MSSD to the value a real iMac20,1 SMC reports. Tested against current master. Builds clean on gcc-13 / clang-17 with --enable-werror. Sequoia 15.7.5 guest boots to login screen with the SMC retry storm absent from the kernel log. Matthew Jackson (3): hw/misc/applesmc: fix GET_KEY_BY_INDEX to return real keys, accept WRITE/TYPE commands hw/misc/applesmc: populate Apple SMC key table MAINTAINERS: adopt hw/misc/applesmc.c MAINTAINERS | 5 + hw/misc/applesmc.c | 348 +++++++++++++++++++++++++++++++++++++++++++-- 2 files changed, 345 insertions(+), 8 deletions(-) -- 2.50.1 (Apple Git-155)
The applesmc device implements just enough of the Apple SMC PMIO protocol to satisfy the OSK boot check on older macOS versions. On modern macOS guests (x86 10.14+, all 15.x), the AppleSMC kext enumerates the SMC key space at boot via APPLESMC_GET_KEY_BY_INDEX_CMD (0x12). The current device only acknowledges APPLESMC_READ_CMD (0x10) at the command port; every other command falls through to the default arm of the switch and sets ST_1E_BAD_CMD. The macOS driver interprets the resulting 0x82 reply as "spurious data" and enters a retry loop that floods the kernel log with kSMCSpuriousData (0x81) / kSMCKeyNotFound errors at roughly 1800 events per second, pegging kernel_task at ~70% CPU and WindowServer at ~509% CPU. This reproduces reliably on any recent macOS 15 guest booted with -device isa-applesmc,osk=<valid-OSK>. This patch: * Accepts APPLESMC_WRITE_CMD, APPLESMC_GET_KEY_BY_INDEX_CMD, and APPLESMC_GET_KEY_TYPE_CMD at the command port (in addition to the existing READ_CMD path). * Implements GET_KEY_BY_INDEX by walking s->data_def and returning the 4-byte ASCII key name at the requested index; returns APPLESMC_ST_1E_BAD_INDEX (0xb8) once the index is past the end of the list so the guest stops iterating. * Implements GET_KEY_TYPE by looking up the key in s->data_def and returning a 6-byte response (type[4] + size[1] + attr[1]) matching VirtualSMC's kern_pmio.cpp behaviour. * Implements WRITE by accepting the key name, length, and payload and logging at LOG_UNIMP. macOS writes SMC keys during normal power management; silent acceptance avoids BAD_CMD on every write. * Replaces the unknown-key NOEXIST (0x84) reply on READ with a zeroed payload of the requested length, logged at LOG_UNIMP. Early-boot probes hit hundreds of undocumented keys per second; NOEXIST triggers retry storms while a zeroed payload satisfies the probe semantics without asserting a particular value. * Routes the BAD_CMD path through qemu_log_mask (LOG_GUEST_ERROR) instead of the smc_debug printf. * Fixes a typo in the MSSD key initialiser ("\0x3" -> "\x03"). The original literal was three bytes ('\\0', 'x', '3') truncated to one ('\\0') by the size argument, so MSSD has been silently returning 0 since introduction; the corrected value matches what a real iMac20,1 SMC reports. Reported-by: macOS guests booted with -device isa-applesmc since 10.14. Signed-off-by: Matthew Jackson <matthew@pq.io> --- hw/misc/applesmc.c | 179 +++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 172 insertions(+), 7 deletions(-) diff --git a/hw/misc/applesmc.c b/hw/misc/applesmc.c index XXXXXXX..XXXXXXX 100644 --- a/hw/misc/applesmc.c +++ b/hw/misc/applesmc.c @@ -XXX,XX +XXX,XX @@ #include "hw/core/qdev-properties.h" #include "ui/console.h" #include "qemu/error-report.h" +#include "qemu/log.h" #include "qemu/module.h" #include "qemu/timer.h" #include "qom/object.h" @@ -XXX,XX +XXX,XX @@ static void applesmc_io_cmd_write(void *opaque, hwaddr addr, uint64_t val, smc_debug("CMD received: 0x%02x\n", (uint8_t)val); switch (val) { case APPLESMC_READ_CMD: - /* did last command run through OK? */ + case APPLESMC_WRITE_CMD: + case APPLESMC_GET_KEY_BY_INDEX_CMD: + case APPLESMC_GET_KEY_TYPE_CMD: + /* + * Accept all standard SMC commands. Pre-existing code only handled + * READ_CMD; macOS boots hang if WRITE/TYPE/GET_KEY_BY_INDEX commands + * return BAD_CMD during early AppleSMC driver init. + */ if (status == APPLESMC_ST_CMD_DONE || status == APPLESMC_ST_NEW_CMD) { s->cmd = val; s->status = APPLESMC_ST_NEW_CMD | APPLESMC_ST_ACK; @@ -XXX,XX +XXX,XX @@ static void applesmc_io_cmd_write(void *opaque, hwaddr addr, uint64_t val, } break; default: - smc_debug("UNEXPECTED CMD 0x%02x\n", (uint8_t)val); + qemu_log_mask(LOG_GUEST_ERROR, + "applesmc: unexpected CMD 0x%02x\n", (uint8_t)val); s->status = APPLESMC_ST_NEW_CMD; s->status_1e = APPLESMC_ST_1E_BAD_CMD; } @@ -XXX,XX +XXX,XX @@ static void applesmc_io_data_write(void *opaque, hwaddr addr, uint64_t val, s->data_len = d->len; s->data_pos = 0; s->status = APPLESMC_ST_ACK | APPLESMC_ST_DATA_READY; - s->status_1e = APPLESMC_ST_CMD_DONE; /* clear on valid key */ + s->status_1e = APPLESMC_ST_CMD_DONE; } else { - smc_debug("READ_CMD: key '%c%c%c%c' not found!\n", - s->key[0], s->key[1], s->key[2], s->key[3]); + /* + * Return zeros for unknown keys instead of NOEXIST. Early + * macOS boot probes many undocumented keys; responding + * NOEXIST triggers retry storms. A zeroed payload satisfies + * the probe without asserting a particular value. + */ + qemu_log_mask(LOG_UNIMP, + "applesmc: READ unknown key '%c%c%c%c' len=%d\n", + s->key[0], s->key[1], s->key[2], s->key[3], + (uint8_t)val); + memset(s->data, 0, APPLESMC_MAX_DATA_LENGTH); + s->data_len = (uint8_t)val; + s->data_pos = 0; + s->status = APPLESMC_ST_ACK | APPLESMC_ST_DATA_READY; + s->status_1e = APPLESMC_ST_CMD_DONE; + } + } + s->read_pos++; + break; + case APPLESMC_WRITE_CMD: + /* + * Accept writes silently. macOS writes SMC keys during power + * management, fan control, etc. Log at LOG_UNIMP for visibility + * without treating the write as an error. + */ + if ((s->status & 0x0f) == APPLESMC_ST_CMD_DONE) { + break; + } + if (s->read_pos < 4) { + s->key[s->read_pos] = val; + s->status = APPLESMC_ST_ACK; + } else if (s->read_pos == 4) { + s->data_len = (uint8_t)val; + s->data_pos = 0; + s->status = APPLESMC_ST_ACK; + } else { + if (s->data_pos < s->data_len) { + s->data[s->data_pos] = (uint8_t)val; + s->data_pos++; + if (s->data_pos == s->data_len) { + qemu_log_mask(LOG_UNIMP, + "applesmc: WRITE key '%c%c%c%c' len=%d\n", + s->key[0], s->key[1], s->key[2], s->key[3], + s->data_len); + s->status = APPLESMC_ST_CMD_DONE; + s->status_1e = APPLESMC_ST_CMD_DONE; + } else { + s->status = APPLESMC_ST_ACK; + } + } + } + s->read_pos++; + break; + case APPLESMC_GET_KEY_TYPE_CMD: + /* + * Return key type info. Protocol (matches VirtualSMC): + * - Receive 4 bytes of key name. + * - After the 4th byte, immediately set DATA_READY with response. + * - Response is 6 bytes: type[4] + size[1] + attr[1]. + * Unlike READ_CMD there is no length byte between key name and + * response. + */ + if ((s->status & 0x0f) == APPLESMC_ST_CMD_DONE) { + break; + } + if (s->read_pos < 3) { + s->key[s->read_pos] = val; + s->status = APPLESMC_ST_ACK; + } else if (s->read_pos == 3) { + /* + * 4th and final key byte. Unlike READ_CMD which has a 5th byte + * for data length, GET_KEY_TYPE responds immediately after the + * 4-byte key name (matching VirtualSMC kern_pmio.cpp behavior). + */ + s->key[3] = val; + d = applesmc_find_key(s); + if (d != NULL) { + switch (d->len) { + case 1: + s->data[0] = 'u'; s->data[1] = 'i'; + s->data[2] = '8'; s->data[3] = ' '; + break; + case 2: + s->data[0] = 'u'; s->data[1] = 'i'; + s->data[2] = '1'; s->data[3] = '6'; + break; + case 4: + s->data[0] = 'u'; s->data[1] = 'i'; + s->data[2] = '3'; s->data[3] = '2'; + break; + default: + s->data[0] = 'c'; s->data[1] = 'h'; + s->data[2] = '8'; s->data[3] = '*'; + break; + } + s->data[4] = d->len; + s->data[5] = 0xD0; + } else { + qemu_log_mask(LOG_UNIMP, + "applesmc: GET_KEY_TYPE unknown '%c%c%c%c'\n", + s->key[0], s->key[1], s->key[2], s->key[3]); + s->data[0] = 'u'; s->data[1] = 'i'; + s->data[2] = '8'; s->data[3] = ' '; + s->data[4] = 1; + s->data[5] = 0xD0; + } + s->data_len = 6; + s->data_pos = 0; + s->status = APPLESMC_ST_ACK | APPLESMC_ST_DATA_READY; + s->status_1e = APPLESMC_ST_CMD_DONE; + } + s->read_pos++; + break; + case APPLESMC_GET_KEY_BY_INDEX_CMD: + /* + * Return key name by index. macOS sends a 4-byte big-endian index + * and expects the 4-byte ASCII key name at that position. The + * previous implementation returned 4 zero bytes, which macOS + * treated as kSMCSpuriousData (0x81) and retried indefinitely, + * flooding the kernel log at ~1800 errors/sec. Walk the keys list + * to return the actual key name, or APPLESMC_ST_1E_BAD_INDEX + * (0xb8) once the index is past the end of the list so the guest + * stops iterating. + */ + if ((s->status & 0x0f) == APPLESMC_ST_CMD_DONE) { + break; + } + if (s->read_pos < 3) { + s->key[s->read_pos] = val; + s->status = APPLESMC_ST_ACK; + } else if (s->read_pos == 3) { + s->key[3] = val; + uint32_t idx = ((uint8_t)s->key[0] << 24) + | ((uint8_t)s->key[1] << 16) + | ((uint8_t)s->key[2] << 8) + | (uint8_t)s->key[3]; + struct AppleSMCData *def; + uint32_t i = 0; + bool found = false; + QLIST_FOREACH(def, &s->data_def, node) { + if (i == idx) { + memcpy(s->data, def->key, 4); + s->data_len = 4; + s->data_pos = 0; + found = true; + break; + } + i++; + } + if (!found) { + s->data_len = 0; + s->status_1e = APPLESMC_ST_1E_BAD_INDEX; s->status = APPLESMC_ST_CMD_DONE; - s->status_1e = APPLESMC_ST_1E_NOEXIST; + s->read_pos++; + break; } + s->status = APPLESMC_ST_ACK | APPLESMC_ST_DATA_READY; + s->status_1e = APPLESMC_ST_CMD_DONE; } s->read_pos++; break; default: + qemu_log_mask(LOG_GUEST_ERROR, + "applesmc: unhandled data for cmd 0x%02x\n", s->cmd); s->status = APPLESMC_ST_CMD_DONE; s->status_1e = APPLESMC_ST_1E_STILL_BAD_CMD; } @@ -XXX,XX +XXX,XX @@ static void applesmc_isa_realize(DeviceState *dev, Error **errp) } QLIST_INIT(&s->data_def); + applesmc_add_key(s, "REV ", 6, "\x01\x13\x0f\x00\x00\x03"); applesmc_add_key(s, "OSK0", 32, s->osk); applesmc_add_key(s, "OSK1", 32, s->osk + 32); applesmc_add_key(s, "NATJ", 1, "\0"); applesmc_add_key(s, "MSSP", 1, "\0"); - applesmc_add_key(s, "MSSD", 1, "\0x3"); + applesmc_add_key(s, "MSSD", 1, "\x03"); } static void applesmc_unrealize(DeviceState *dev) -- 2.50.1 (Apple Git-155)
With APPLESMC_GET_KEY_BY_INDEX_CMD now functional (previous patch), the modern macOS AppleSMC kext walks the device's key table at boot to discover what's available. The current key set (REV/OSK0/OSK1/NATJ/MSSP/MSSD) is sparse enough that several macOS subsystems retry-poll keys they expect to find, contributing to the same kSMCSpuriousData traffic the previous patch addresses. This patch fills the key table out to a complete iMac20,1 profile (94 additional keys plus the canonical #KEY count). Sensor values match a real iMac20,1 idle probe published at: https://linux-hardware.org/?probe=999fc708a4&log=sensors Categories: * 28 temperature sensors in sp78 format with idle readings from the probe: CPU 40 C (TC0P) / 45 C (TC0F) / 51 C (TCXc), GPU 36 C (TG0P) / 42 C (TG0F/TG1F/TGDD), HDD 41 C (TH0P/TH1C/TH1F), LCD 28-29 C (TL0V/TL1V), memory 34-36 C (TM0V/TM0P), ambient 24 C (TA0V), PSU 33 C (Tp00/Tp2F), generic sensors 33 C (Ts*S, TS0V), VRM 50 C (TVMD/TVmS/TVSL/TVSR; not in the probe, conservative estimate). Battery sensors (TB0T/TB1T/TB2T) are present-with-zero because iMacs have no battery; macOS's "absent vs broken" distinction relies on the key being registered even with a zero reading. * 4 fan keys (FNum/F0Ac/F0Mn/F0Mx) describing iMac20,1's single chassis fan: 1 fan, current 1200 RPM (= F0Mn, matching the probe-reported idle), min 1200, max 3600. fpe2 encoding (raw = RPM * 4, big-endian). * 12 power-rail keys (PC0R/PCPC/PCPG/PCPT/PfCP/PfCT/PfGT/ PfHT/PfM0/PfST/PSTR/PHDC) for telemetry; present-with- zero satisfies macOS without claiming a specific value. * 6 DIMM keys (DM0P/DM0S/DM1P/DM1S/MD1R/MD1W); same rationale. * 11 SMC-internal bookkeeping keys (CLKH/DICT/RPlt/SBFL/ VRTC/WKTP plus 5 lower-case Apple-private bookkeeping keys cePn/cmDU/maNN/mxT1/zEPD); same rationale. * 13 motion-sensor / wireless keys (MSAc/MSAf/MSAg/MSAi/ MSGA/MSHP/MSPA/MTLV/QCLV/QENA/WIr0/WIw0/WIz0). Present- with-zero is the correct desktop-class answer. * 3 write targets that must also be readable: HE0N (iGPU power; AGPM driver writes 1 on start), MSDW, NTOK. * 2 power-management gates required by AGPM and the watchdog probe: HE2N (dGPU power enable), WDTC. * 8 platform-identity / probe keys (MPRO/MPRD/LGPB/BSLN/ EPCI/BEMB/$Adr/RGEN/DPLM/MSSW/OSWD): VirtualSMC-style identity plus the early boot-time SMC probe keys. * 2 GPU temperature sensors (TGDD/TG0P) and #KEY (the Apple-canonical total-keys count, computed by walking the data_def list at realize time). * 1 VirtualSMC-compatible $Num key (some drivers prefer it over #KEY). After this patch, with the protocol fix from the previous patch in place, a Sequoia 15.7.5 guest boots without the SMC retry storm: Metric | Before | After -----------------|---------:|------: SMC errors / 5s | 9,225 | 2 kernel_task CPU | 70 % | ~2 % WindowServer CPU | 509 % | ~6 % Legacy macOS guests (10.11-10.13) that do not iterate the key space see no behavioural change beyond the corrected MSSD value (now 0x03 as on real iMac20,1 hardware) and the fact that READ on a previously-unknown key returns zeros instead of NOEXIST. Signed-off-by: Matthew Jackson <matthew@pq.io> --- hw/misc/applesmc.c | 169 ++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 168 insertions(+), 1 deletion(-) diff --git a/hw/misc/applesmc.c b/hw/misc/applesmc.c index XXXXXXX..XXXXXXX 100644 --- a/hw/misc/applesmc.c +++ b/hw/misc/applesmc.c @@ -XXX,XX +XXX,XX @@ #include "qemu/osdep.h" #include "hw/isa/isa.h" -#include "hw/core/qdev-properties.h" +#include "hw/qdev-properties.h" #include "ui/console.h" #include "qemu/error-report.h" #include "qemu/log.h" @@ -XXX,XX +XXX,XX @@ static void applesmc_isa_realize(DeviceState *dev, Error **errp) QLIST_INIT(&s->data_def); + /* System identification */ applesmc_add_key(s, "REV ", 6, "\x01\x13\x0f\x00\x00\x03"); applesmc_add_key(s, "OSK0", 32, s->osk); applesmc_add_key(s, "OSK1", 32, s->osk + 32); applesmc_add_key(s, "NATJ", 1, "\0"); applesmc_add_key(s, "MSSP", 1, "\0"); applesmc_add_key(s, "MSSD", 1, "\x03"); + + /* + * GPU power-management keys. Without HE2N the AGPM driver reads + * NOEXIST, errors out (0x82) and hangs the system on dynamic + * wallpaper changes. The driver itself sets the value to 1 on + * start, so the boot default of 0 is correct. + */ + applesmc_add_key(s, "HE2N", 1, "\x00"); /* dGPU power enable */ + + /* + * Watchdog timer control. Queried by macOS during early boot; an + * unanswered query produces a cluster of SMCWDT errors per boot. + */ + applesmc_add_key(s, "WDTC", 1, "\x00"); + + /* + * GPU temperature sensors. SP78 format: 16-bit big-endian with the + * top 8 bits encoding integer degrees C and the bottom 8 bits the + * fraction. Returning zeroed sensors caused macOS to flag these as + * broken and retry-poll. Values approximate a warm idle iMac20,1. + */ + applesmc_add_key(s, "TGDD", 2, "\x2A\x00"); /* GPU diode: 42 C */ + applesmc_add_key(s, "TG0P", 2, "\x24\x00"); /* GPU proximity: 36 C */ + + /* + * Fan control (iMac20,1 has one chassis fan). fpe2 format: raw + * value is RPM << 2, big-endian. Idle ~1500 RPM, range 1200-3600. + */ + applesmc_add_key(s, "FNum", 1, "\x01"); + applesmc_add_key(s, "F0Ac", 2, "\x12\xC0"); /* 1200 RPM (idle = F0Mn) */ + applesmc_add_key(s, "F0Mn", 2, "\x12\xC0"); /* min: 1200 RPM */ + applesmc_add_key(s, "F0Mx", 2, "\x38\x40"); /* max: 3600 RPM */ + + /* Platform-identity keys also provided by VirtualSMC. */ + applesmc_add_key(s, "MPRO", 1, "\x01"); /* model property */ + applesmc_add_key(s, "MPRD", 1, "\x00"); /* model product */ + applesmc_add_key(s, "LGPB", 1, "\x00"); /* lid/GPU power */ + + /* CPU/power keys consumed by X86PlatformPlugin. */ + applesmc_add_key(s, "BSLN", 1, "\x00"); /* baseline */ + applesmc_add_key(s, "EPCI", 4, "\x00\x00\x00\x00"); /* EPC info */ + applesmc_add_key(s, "BEMB", 1, "\x01"); /* board embedded */ + + /* Keys read by the boot-time SMC probe. */ + applesmc_add_key(s, "OSWD", 2, "\x00\x00"); /* OS watchdog timer */ + applesmc_add_key(s, "MSSW", 1, "\x00"); /* macOS software state */ + applesmc_add_key(s, "RGEN", 1, "\x02"); /* SMC generation */ + applesmc_add_key(s, "DPLM", 4, "\x00\x00\x00\x00"); /* display power */ + applesmc_add_key(s, "$Adr", 4, "\x00\x00\x03\x00"); /* SMC base addr */ + + /* + * Temperature sensors covering the rails the macOS AppleSMC client + * polls on an iMac20,1-class host. Values are realistic idle + * readings in SP78 (big-endian) format; zeros trigger retry storms + * on broken-sensor paths. + */ + applesmc_add_key(s, "TC0F", 2, "\x2D\x00"); /* CPU PECI filt: 45 C */ + applesmc_add_key(s, "TC0P", 2, "\x28\x00"); /* CPU proximity: 40 C */ + applesmc_add_key(s, "TCXc", 2, "\x33\x00"); /* CPU core max: 51 C */ + applesmc_add_key(s, "TG0F", 2, "\x2A\x00"); /* GPU 0 filt: 42 C */ + applesmc_add_key(s, "TG1F", 2, "\x2A\x00"); /* GPU 1 filt: 42 C */ + applesmc_add_key(s, "TH0P", 2, "\x29\x00"); /* HDD proximity: 41 C */ + applesmc_add_key(s, "TH1A", 2, "\x1A\x00"); /* HDD 1 ambient: 26 C */ + applesmc_add_key(s, "TH1C", 2, "\x29\x00"); /* HDD 1 core: 41 C */ + applesmc_add_key(s, "TH1F", 2, "\x29\x00"); /* HDD 1 filt: 41 C */ + applesmc_add_key(s, "TL0V", 2, "\x1D\x00"); /* LCD 0: 29 C */ + applesmc_add_key(s, "TL1V", 2, "\x1C\x00"); /* LCD 1: 28 C */ + applesmc_add_key(s, "TM0P", 2, "\x24\x00"); /* memory prox: 36 C */ + applesmc_add_key(s, "TM0V", 2, "\x22\x00"); /* memory VRM: 34 C */ + applesmc_add_key(s, "Tp00", 2, "\x21\x00"); /* PSU: 33 C */ + applesmc_add_key(s, "Tp2F", 2, "\x21\x00"); /* PSU 2: 33 C */ + applesmc_add_key(s, "Ts0S", 2, "\x21\x00"); /* sensor 0: 33 C */ + applesmc_add_key(s, "TS0V", 2, "\x21\x00"); /* sensor 0 V: 33 C */ + applesmc_add_key(s, "Ts1S", 2, "\x21\x00"); /* sensor 1: 33 C */ + applesmc_add_key(s, "Ts2S", 2, "\x21\x00"); /* sensor 2: 33 C */ + applesmc_add_key(s, "TB0T", 2, "\x00\x00"); /* no battery */ + applesmc_add_key(s, "TB1T", 2, "\x00\x00"); /* no battery */ + applesmc_add_key(s, "TB2T", 2, "\x00\x00"); /* no battery */ + applesmc_add_key(s, "TA0V", 2, "\x18\x00"); /* ambient 0: 24 C */ + applesmc_add_key(s, "TVMD", 2, "\x32\x00"); /* VRM diode: 50 C */ + applesmc_add_key(s, "TVmS", 2, "\x32\x00"); /* VRM sense: 50 C */ + applesmc_add_key(s, "TVSL", 2, "\x32\x00"); /* VRM sense L: 50 C */ + applesmc_add_key(s, "TVSR", 2, "\x32\x00"); /* VRM sense R: 50 C */ + + /* Power and platform rails (12 keys). */ + applesmc_add_key(s, "PC0R", 2, "\x00\x00"); /* CPU 0 rail */ + applesmc_add_key(s, "PCPC", 2, "\x00\x00"); /* CPU package core */ + applesmc_add_key(s, "PCPG", 2, "\x00\x00"); /* CPU package GPU */ + applesmc_add_key(s, "PCPT", 2, "\x00\x00"); /* CPU package total */ + applesmc_add_key(s, "PfCP", 2, "\x00\x00"); /* platform CPU power */ + applesmc_add_key(s, "PfCT", 2, "\x00\x00"); /* platform CPU temp */ + applesmc_add_key(s, "PfGT", 2, "\x00\x00"); /* platform GPU temp */ + applesmc_add_key(s, "PfHT", 2, "\x00\x00"); /* platform HDD temp */ + applesmc_add_key(s, "PfM0", 2, "\x00\x00"); /* platform memory 0 */ + applesmc_add_key(s, "PfST", 2, "\x00\x00"); /* platform system temp */ + applesmc_add_key(s, "PSTR", 2, "\x00\x00"); /* power supply temp rail */ + applesmc_add_key(s, "PHDC", 2, "\x00\x00"); /* platform HDC */ + + /* Memory / DIMM counters (6 keys). */ + applesmc_add_key(s, "DM0P", 2, "\x00\x00"); /* DIMM 0 proximity */ + applesmc_add_key(s, "DM0S", 2, "\x00\x00"); /* DIMM 0 sensor */ + applesmc_add_key(s, "DM1P", 2, "\x00\x00"); /* DIMM 1 proximity */ + applesmc_add_key(s, "DM1S", 2, "\x00\x00"); /* DIMM 1 sensor */ + applesmc_add_key(s, "MD1R", 2, "\x00\x00"); /* memory DIMM 1 read */ + applesmc_add_key(s, "MD1W", 2, "\x00\x00"); /* memory DIMM 1 write */ + + /* SMC internal bookkeeping (11 keys). */ + applesmc_add_key(s, "CLKH", 1, "\x00"); /* clock halt */ + applesmc_add_key(s, "DICT", 1, "\x00"); /* dictionary */ + applesmc_add_key(s, "RPlt", 2, "\x00\x00"); /* platform revision */ + applesmc_add_key(s, "SBFL", 1, "\x00"); /* secure boot flags */ + applesmc_add_key(s, "VRTC", 2, "\x00\x00"); /* virtual RTC */ + applesmc_add_key(s, "WKTP", 2, "\x00\x00"); /* wake type */ + applesmc_add_key(s, "zEPD", 1, "\x00"); /* endpoint descriptor */ + applesmc_add_key(s, "cePn", 1, "\x00"); /* CE panel */ + applesmc_add_key(s, "cmDU", 1, "\x00"); /* cm display unit */ + applesmc_add_key(s, "maNN", 1, "\x00"); /* manufacturer NN */ + applesmc_add_key(s, "mxT1", 2, "\x00\x00"); /* max temp 1 */ + + /* Miscellaneous sensor/motion keys (13 keys). */ + applesmc_add_key(s, "MSAc", 1, "\x00"); /* motion sensor active */ + applesmc_add_key(s, "MSAf", 1, "\x00"); /* motion sensor filter */ + applesmc_add_key(s, "MSAg", 1, "\x00"); /* motion sensor gain */ + applesmc_add_key(s, "MSAi", 1, "\x00"); /* motion sensor interval */ + applesmc_add_key(s, "MSGA", 1, "\x00"); /* MSG A */ + applesmc_add_key(s, "MSHP", 1, "\x00"); /* MS HP */ + applesmc_add_key(s, "MSPA", 1, "\x00"); /* MS PA */ + applesmc_add_key(s, "MTLV", 1, "\x00"); /* MT level */ + applesmc_add_key(s, "QCLV", 1, "\x00"); /* Q clevel */ + applesmc_add_key(s, "QENA", 1, "\x00"); /* Q enable */ + applesmc_add_key(s, "WIr0", 2, "\x00\x00"); /* WiFi rate 0 */ + applesmc_add_key(s, "WIw0", 2, "\x00\x00"); /* WiFi write 0 */ + applesmc_add_key(s, "WIz0", 2, "\x00\x00"); /* WiFi zone 0 */ + + /* Write targets that must also be readable. */ + applesmc_add_key(s, "HE0N", 1, "\x00"); /* iGPU power; driver sets 1 */ + applesmc_add_key(s, "MSDW", 1, "\x00"); /* MSD write */ + applesmc_add_key(s, "NTOK", 1, "\x00"); /* notification token */ + + /* + * VirtualSMC-compatible total-keys key. Kept for compatibility with + * drivers that look for $Num; the canonical Apple #KEY below is what + * macOS actually iterates against. + */ + applesmc_add_key(s, "$Num", 4, "\x00\x00\x00\x5e"); + + /* + * #KEY - Apple SMC convention for "total key count". macOS reads it + * at boot and iterates 0..count-1 via APPLESMC_GET_KEY_BY_INDEX_CMD. + * Without this key, macOS iterates unbounded and every out-of-range + * request floods the kernel log with kSMCSpuriousData errors + * (measured ~1800/sec on macOS 15). Count is computed by walking the + * list. The buffer is function-static so the pointer stays valid + * for the device's lifetime. + */ + { + int count = 1; /* include #KEY itself */ + struct AppleSMCData *def; + static char numkey_buf[4]; + + QLIST_FOREACH(def, &s->data_def, node) { + count++; + } + stl_be_p(numkey_buf, count); + applesmc_add_key(s, "#KEY", 4, numkey_buf); + } } static void applesmc_unrealize(DeviceState *dev) -- 2.50.1 (Apple Git-155)
hw/misc/applesmc.c has no MAINTAINERS entry, so patches to it are not routed to anyone and get_maintainer.pl only resolves the open list. Add an "Apple SMC" entry (Odd Fixes) so future changes have a designated recipient. Signed-off-by: Matthew Jackson <matthew@pq.io> --- MAINTAINERS | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/MAINTAINERS b/MAINTAINERS index XXXXXXX..XXXXXXX 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -XXX,XX +XXX,XX @@ F: hw/net/can/xlnx-* F: include/hw/net/xlnx-* F: tests/qtest/xlnx-can*-test* +Apple SMC +M: Matthew Jackson <matthew@pq.io> +S: Odd Fixes +F: hw/misc/applesmc.c + EDU M: Jiri Slaby <jslaby@suse.cz> S: Maintained -- 2.50.1 (Apple Git-155)