[xen staging-4.20] x86/mwait-idle: add Sierra Forest SoC support

[patchbot@xxxxxxx]

commit a634a48b48e347a02b61b7556df128a2bea23e13
Author:     Artem Bityutskiy <artem.bityutskiy@xxxxxxxxxxxxxxx>
AuthorDate: Tue Jul 22 09:51:38 2025 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue Jul 22 09:51:38 2025 +0200

    x86/mwait-idle: add Sierra Forest SoC support
    
    Add Sierra Forest SoC C-states, which are C1, C1E, C6S, and C6SP.
    
    Sierra Forest SoC is built with modules, each module includes 4 cores
    (Crestmont microarchitecture). There is one L2 cache per module, shared
    between the 4 cores.
    
    There is no core C6 state, but there is C6S state, which has module scope:
    when all 4 cores request C6S, the entire module (4 cores + L2 cache)
    enters the low power state.
    
    C6SP state has package scope - when all modules in the package enter C6S,
    the package enters the power state mode.
    
    Signed-off-by: Artem Bityutskiy <artem.bityutskiy@xxxxxxxxxxxxxxx>
    Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
    Origin: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 
92813fd5b156
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Acked-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    master commit: edd31f0fe9d74ee0bd3060900a5a68bb2d02cacb
    master date: 2025-07-09 11:01:50 +0200
---
 xen/arch/x86/cpu/mwait-idle.c | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/xen/arch/x86/cpu/mwait-idle.c b/xen/arch/x86/cpu/mwait-idle.c
index 77423483e7..cca3fd3d73 100644
--- a/xen/arch/x86/cpu/mwait-idle.c
+++ b/xen/arch/x86/cpu/mwait-idle.c
@@ -950,6 +950,34 @@ static const struct cpuidle_state grr_cstates[] = {
        {}
 };
 
+static const struct cpuidle_state srf_cstates[] = {
+       {
+               .name = "C1",
+               .flags = MWAIT2flg(0x00),
+               .exit_latency = 1,
+               .target_residency = 1,
+       },
+       {
+               .name = "C1E",
+               .flags = MWAIT2flg(0x01),
+               .exit_latency = 2,
+               .target_residency = 10,
+       },
+       {
+               .name = "C6S",
+               .flags = MWAIT2flg(0x22) | CPUIDLE_FLAG_TLB_FLUSHED,
+               .exit_latency = 270,
+               .target_residency = 700,
+       },
+       {
+               .name = "C6SP",
+               .flags = MWAIT2flg(0x23) | CPUIDLE_FLAG_TLB_FLUSHED,
+               .exit_latency = 310,
+               .target_residency = 900,
+       },
+       {}
+};
+
 static void cf_check mwait_idle(void)
 {
        unsigned int cpu = smp_processor_id();
@@ -1199,6 +1227,11 @@ static const struct idle_cpu idle_cpu_grr = {
        .c1e_promotion = C1E_PROMOTION_DISABLE,
 };
 
+static const struct idle_cpu idle_cpu_srf = {
+       .state_table = srf_cstates,
+       .c1e_promotion = C1E_PROMOTION_DISABLE,
+};
+
 #define ICPU(model, cpu) \
        { X86_VENDOR_INTEL, 6, INTEL_FAM6_ ## model, X86_FEATURE_ALWAYS, \
          &idle_cpu_ ## cpu}
@@ -1248,6 +1281,7 @@ static const struct x86_cpu_id intel_idle_ids[] 
__initconstrel = {
        ICPU(ATOM_GOLDMONT_D,           dnv),
        ICPU(ATOM_TREMONT_D,            snr),
        ICPU(ATOM_CRESTMONT,            grr),
+       ICPU(ATOM_CRESTMONT_X,          srf),
        {}
 };
 
--
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