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Revert "KVM: PPC: Book3S HV: POWER9 does not require secondary thread management"

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This reverts commit 94a04bc25a.

In order to run HPT guests on a radix POWER9 host, we will have to run
the host in single-threaded mode, because POWER9 processors do not
currently support running some threads of a core in HPT mode while
others are in radix mode ("mixed mode").

That means that we will need the same mechanisms that are used on
POWER8 to make the secondary threads available to KVM, which were
disabled on POWER9 by commit 94a04bc25a.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Paul Mackerras 2017-10-19 15:14:20 +11:00 committed by Michael Ellerman
parent e19b205be4
commit 31a4d4480c
4 changed files with 12 additions and 48 deletions
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4
arch/powerpc/include/asm/kvm_book3s_asm.h
View File

@ -104,10 +104,6 @@ struct kvmppc_host_state {
u8 napping;
#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
/*
* hwthread_req/hwthread_state pair is used to pull sibling threads
* out of guest on pre-ISAv3.0B CPUs where threads share MMU.
*/
u8 hwthread_req;
u8 hwthread_state;
u8 host_ipi;

35
arch/powerpc/kernel/idle_book3s.S
View File

@ -319,20 +319,13 @@ enter_winkle:
/*
* r3 - PSSCR value corresponding to the requested stop state.
*/
power_enter_stop:
#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
power_enter_stop_kvm_rm:
/*
* This is currently unused because POWER9 KVM does not have to
* gather secondary threads into sibling mode, but the code is
* here in case that function is required.
*
* Tell KVM we're entering idle.
*/
/* Tell KVM we're entering idle */
li r4,KVM_HWTHREAD_IN_IDLE
/* DO THIS IN REAL MODE! See comment above. */
stb r4,HSTATE_HWTHREAD_STATE(r13)
#endif
power_enter_stop:
/*
* Check if we are executing the lite variant with ESL=EC=0
*/
@ -496,18 +489,6 @@ pnv_powersave_wakeup_mce:
b pnv_powersave_wakeup
#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
kvm_start_guest_check:
li r0,KVM_HWTHREAD_IN_KERNEL
stb r0,HSTATE_HWTHREAD_STATE(r13)
/* Order setting hwthread_state vs. testing hwthread_req */
sync
lbz r0,HSTATE_HWTHREAD_REQ(r13)
cmpwi r0,0
beqlr
b kvm_start_guest
#endif
/*
* Called from reset vector for powersave wakeups.
* cr3 - set to gt if waking up with partial/complete hypervisor state loss
@ -532,9 +513,15 @@ ALT_FTR_SECTION_END_IFSET(CPU_FTR_ARCH_300)
mr r3,r12
#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
BEGIN_FTR_SECTION
bl kvm_start_guest_check
END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_300)
li r0,KVM_HWTHREAD_IN_KERNEL
stb r0,HSTATE_HWTHREAD_STATE(r13)
/* Order setting hwthread_state vs. testing hwthread_req */
sync
lbz r0,HSTATE_HWTHREAD_REQ(r13)
cmpwi r0,0
beq 1f
b kvm_start_guest
1:
#endif
/* Return SRR1 from power7_nap() */

13
arch/powerpc/kvm/book3s_hv.c
View File

@ -2117,15 +2117,6 @@ static int kvmppc_grab_hwthread(int cpu)
struct paca_struct *tpaca;
long timeout = 10000;
/*
* ISA v3.0 idle routines do not set hwthread_state or test
* hwthread_req, so they can not grab idle threads.
*/
if (cpu_has_feature(CPU_FTR_ARCH_300)) {
WARN(1, "KVM: can not control sibling threads\n");
return -EBUSY;
}
tpaca = &paca[cpu];
/* Ensure the thread won't go into the kernel if it wakes */
@ -2160,12 +2151,10 @@ static void kvmppc_release_hwthread(int cpu)
struct paca_struct *tpaca;
tpaca = &paca[cpu];
tpaca->kvm_hstate.hwthread_req = 0;
tpaca->kvm_hstate.kvm_vcpu = NULL;
tpaca->kvm_hstate.kvm_vcore = NULL;
tpaca->kvm_hstate.kvm_split_mode = NULL;
if (!cpu_has_feature(CPU_FTR_ARCH_300))
tpaca->kvm_hstate.hwthread_req = 0;
}
static void radix_flush_cpu(struct kvm *kvm, int cpu, struct kvm_vcpu *vcpu)

8
arch/powerpc/kvm/book3s_hv_rmhandlers.S
View File

@ -149,11 +149,9 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)
subf r4, r4, r3
mtspr SPRN_DEC, r4
BEGIN_FTR_SECTION
/* hwthread_req may have got set by cede or no vcpu, so clear it */
li r0, 0
stb r0, HSTATE_HWTHREAD_REQ(r13)
END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_300)
/*
* For external interrupts we need to call the Linux
@ -316,7 +314,6 @@ kvm_novcpu_exit:
* Relocation is off and most register values are lost.
* r13 points to the PACA.
* r3 contains the SRR1 wakeup value, SRR1 is trashed.
* This is not used by ISAv3.0B processors.
*/
.globl kvm_start_guest
kvm_start_guest:
@ -435,9 +432,6 @@ kvm_secondary_got_guest:
* While waiting we also need to check if we get given a vcpu to run.
*/
kvm_no_guest:
BEGIN_FTR_SECTION
twi 31,0,0
END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300)
lbz r3, HSTATE_HWTHREAD_REQ(r13)
cmpwi r3, 0
bne 53f
@ -2531,10 +2525,8 @@ kvm_do_nap:
clrrdi r0, r0, 1
mtspr SPRN_CTRLT, r0
BEGIN_FTR_SECTION
li r0,1
stb r0,HSTATE_HWTHREAD_REQ(r13)
END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_300)
mfspr r5,SPRN_LPCR
ori r5,r5,LPCR_PECE0 | LPCR_PECE1
BEGIN_FTR_SECTION