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KVM: PPC: Book3S HV P9: implement hash host / hash guest support 

Implement support for hash guests under hash host. This has to save and
restore the host SLB, and ensure that the MMU is off while switching
into the guest SLB.

POWER9 and later CPUs now always go via the P9 path. The "fast" guest
mode is now renamed to the P9 mode, which is consistent with its
functionality and the rest of the naming.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210528090752.3542186-32-npiggin@gmail.com
This commit is contained in:
Nicholas Piggin 2021-05-28 19:07:51 +10:00 committed by Michael Ellerman
parent 079a09a500
commit 0bf7e1b2e9
4 changed files with 44 additions and 13 deletions
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2
arch/powerpc/include/asm/kvm_asm.h
View File

@ -147,7 +147,7 @@
#define KVM_GUEST_MODE_SKIP 2
#define KVM_GUEST_MODE_GUEST_HV 3
#define KVM_GUEST_MODE_HOST_HV 4
#define KVM_GUEST_MODE_HV_FAST 5 /* ISA >= v3.0 host radix */
#define KVM_GUEST_MODE_HV_P9 5 /* ISA >= v3.0 path */
#define KVM_INST_FETCH_FAILED -1

15
arch/powerpc/kvm/book3s_64_entry.S
View File

@ -36,7 +36,7 @@
kvmppc_hcall:
#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
lbz r10,HSTATE_IN_GUEST(r13)
cmpwi r10,KVM_GUEST_MODE_HV_FAST
cmpwi r10,KVM_GUEST_MODE_HV_P9
beq kvmppc_p9_exit_hcall
#endif
ld r10,PACA_EXGEN+EX_R13(r13)
@ -68,7 +68,7 @@ kvmppc_interrupt:
#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
std r10,HSTATE_SCRATCH0(r13)
lbz r10,HSTATE_IN_GUEST(r13)
cmpwi r10,KVM_GUEST_MODE_HV_FAST
cmpwi r10,KVM_GUEST_MODE_HV_P9
beq kvmppc_p9_exit_interrupt
ld r10,HSTATE_SCRATCH0(r13)
#endif
@ -183,8 +183,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
/*
* void kvmppc_p9_enter_guest(struct vcpu *vcpu);
*
* Enter the guest on a ISAv3.0 or later system where we have exactly
* one vcpu per vcore, and the host is radix.
* Enter the guest on a ISAv3.0 or later system.
*/
.balign IFETCH_ALIGN_BYTES
_GLOBAL(kvmppc_p9_enter_guest)
@ -284,7 +283,7 @@ kvmppc_p9_exit_hcall:
.balign IFETCH_ALIGN_BYTES
kvmppc_p9_exit_interrupt:
/*
* If set to KVM_GUEST_MODE_HV_FAST but we're still in the
* If set to KVM_GUEST_MODE_HV_P9 but we're still in the
* hypervisor, that means we can't return from the entry stack.
*/
rldicl. r10,r12,64-MSR_HV_LG,63
@ -358,6 +357,12 @@ kvmppc_p9_exit_interrupt:
* effort for a small bit of code. Lots of other things to do first.
*/
kvmppc_p9_bad_interrupt:
BEGIN_MMU_FTR_SECTION
/*
* Hash host doesn't try to recover MMU (requires host SLB reload)
*/
b .
END_MMU_FTR_SECTION_IFCLR(MMU_FTR_TYPE_RADIX)
/*
* Clean up guest registers to give host a chance to run.
*/

4
arch/powerpc/kvm/book3s_hv.c
View File

@ -4511,7 +4511,7 @@ static int kvmppc_vcpu_run_hv(struct kvm_vcpu *vcpu)
vcpu->arch.state = KVMPPC_VCPU_BUSY_IN_HOST;
do {
if (radix_enabled())
if (cpu_has_feature(CPU_FTR_ARCH_300))
r = kvmhv_run_single_vcpu(vcpu, ~(u64)0,
vcpu->arch.vcore->lpcr);
else
@ -5599,6 +5599,8 @@ static int kvmhv_enable_nested(struct kvm *kvm)
return -EPERM;
if (!cpu_has_feature(CPU_FTR_ARCH_300))
return -ENODEV;
if (!radix_enabled())
return -ENODEV;
/* kvm == NULL means the caller is testing if the capability exists */
if (kvm)

36
arch/powerpc/kvm/book3s_hv_p9_entry.c
View File

@ -130,7 +130,7 @@ static void switch_mmu_to_guest_hpt(struct kvm *kvm, struct kvm_vcpu *vcpu, u64
isync();
}
static void switch_mmu_to_host_radix(struct kvm *kvm, u32 pid)
static void switch_mmu_to_host(struct kvm *kvm, u32 pid)
{
isync();
mtspr(SPRN_PID, pid);
@ -139,6 +139,22 @@ static void switch_mmu_to_host_radix(struct kvm *kvm, u32 pid)
isync();
mtspr(SPRN_LPCR, kvm->arch.host_lpcr);
isync();
if (!radix_enabled())
slb_restore_bolted_realmode();
}
static void save_clear_host_mmu(struct kvm *kvm)
{
if (!radix_enabled()) {
/*
* Hash host could save and restore host SLB entries to
* reduce SLB fault overheads of VM exits, but for now the
* existing code clears all entries and restores just the
* bolted ones when switching back to host.
*/
slb_clear_invalidate_partition();
}
}
static void save_clear_guest_mmu(struct kvm *kvm, struct kvm_vcpu *vcpu)
@ -271,16 +287,24 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpc
mtspr(SPRN_AMOR, ~0UL);
local_paca->kvm_hstate.in_guest = KVM_GUEST_MODE_HV_FAST;
if (kvm_is_radix(kvm)) {
if (cpu_has_feature(CPU_FTR_P9_RADIX_PREFETCH_BUG))
local_paca->kvm_hstate.in_guest = KVM_GUEST_MODE_HV_P9;
/*
* Hash host, hash guest, or radix guest with prefetch bug, all have
* to disable the MMU before switching to guest MMU state.
*/
if (!radix_enabled() || !kvm_is_radix(kvm) ||
cpu_has_feature(CPU_FTR_P9_RADIX_PREFETCH_BUG))
__mtmsrd(msr & ~(MSR_IR|MSR_DR|MSR_RI), 0);
save_clear_host_mmu(kvm);
if (kvm_is_radix(kvm)) {
switch_mmu_to_guest_radix(kvm, vcpu, lpcr);
if (!cpu_has_feature(CPU_FTR_P9_RADIX_PREFETCH_BUG))
__mtmsrd(0, 1); /* clear RI */
} else {
__mtmsrd(msr & ~(MSR_IR|MSR_DR|MSR_RI), 0);
switch_mmu_to_guest_hpt(kvm, vcpu, lpcr);
}
@ -468,7 +492,7 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpc
mtspr(SPRN_HDEC, 0x7fffffff);
save_clear_guest_mmu(kvm, vcpu);
switch_mmu_to_host_radix(kvm, host_pidr);
switch_mmu_to_host(kvm, host_pidr);
local_paca->kvm_hstate.in_guest = KVM_GUEST_MODE_NONE;
/*