motorhead/qemu
1
0
Fork 0
mirror of https://github.com/Motorhead1991/qemu.git synced 2025-08-04 16:23:55 -06:00
Code Issues Projects Releases Packages Wiki Activity Actions

target/ppc: Add new hflags to support BHRB

Browse source 
This commit is preparatory to the addition of Branch History
Rolling Buffer (BHRB) functionality, which is being provided
today starting with the P8 processor.

BHRB uses several SPR register fields to control whether or not
a branch instruction's address (and sometimes target address)
should be recorded.  Checking each of these fields with each
branch instruction using jitted code would lead to a significant
decrease in performance.

Therefore, it was decided that BHRB configuration bits that are
not expected to change frequently should have their state summarized
in an hflag so that the amount of checking done by jitted code can
be reduced.

This commit contains the changes for summarizing the state of the
following register fields in the HFLAGS_BHRB_ENABLE hflag:

	MMCR0[FCP] - Determines if BHRB recording is frozen in the
                     problem state

	MMCR0[FCPC] - A modifier for MMCR0[FCP]

	MMCRA[BHRBRD] - Disables all BHRB recording for a thread

Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Glenn Miles <milesg@linux.vnet.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
This commit is contained in:
Glenn Miles 2024-03-28 20:41:29 +10:00 • committed by Nicholas Piggin
parent 687a30ad3c
commit a7138e28a2
10 changed files with 67 additions and 9 deletions
Download patch file Download diff file Expand all files Collapse all files

4
target/ppc/cpu_init.c
View file

@ -5152,7 +5152,7 @@ static void register_book3s_pmu_sup_sprs(CPUPPCState *env)
KVM_REG_PPC_MMCR1, 0x00000000);
spr_register_kvm(env, SPR_POWER_MMCRA, "MMCRA",
SPR_NOACCESS, SPR_NOACCESS,
&spr_read_generic, &spr_write_generic,
&spr_read_generic, &spr_write_MMCRA,
KVM_REG_PPC_MMCRA, 0x00000000);
spr_register_kvm(env, SPR_POWER_PMC1, "PMC1",
SPR_NOACCESS, SPR_NOACCESS,
@ -7196,7 +7196,7 @@ static void ppc_cpu_reset_hold(Object *obj, ResetType type)
if (env->mmu_model != POWERPC_MMU_REAL) {
ppc_tlb_invalidate_all(env);
}
pmu_mmcr01_updated(env);
pmu_mmcr01a_updated(env);
}
/* clean any pending stop state */