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authorNicholas Piggin <npiggin@gmail.com>2021-05-28 19:07:40 +1000
committerMichael Ellerman <mpe@ellerman.id.au>2021-06-10 22:12:14 +1000
commit41f779917669fcc28a7f5646d1f7a85043c9d152 (patch)
treebf4fbc5a080c2558dce60998ed668c7bf4b93264 /arch
parentedba6aff4f2c3893e168df6a2e9a20f3c39b0b30 (diff)
downloadlinux-41f779917669fcc28a7f5646d1f7a85043c9d152.tar.bz2
KVM: PPC: Book3S HV P9: Switch to guest MMU context as late as possible
Move MMU context switch as late as reasonably possible to minimise code running with guest context switched in. This becomes more important when this code may run in real-mode, with later changes. Move WARN_ON as early as possible so program check interrupts are less likely to tangle everything up. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210528090752.3542186-21-npiggin@gmail.com
Diffstat (limited to 'arch')
-rw-r--r--arch/powerpc/kvm/book3s_hv_p9_entry.c40
1 files changed, 20 insertions, 20 deletions
diff --git a/arch/powerpc/kvm/book3s_hv_p9_entry.c b/arch/powerpc/kvm/book3s_hv_p9_entry.c
index f24a12632b72..0b5bd00c9d0f 100644
--- a/arch/powerpc/kvm/book3s_hv_p9_entry.c
+++ b/arch/powerpc/kvm/book3s_hv_p9_entry.c
@@ -138,8 +138,13 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpc
if (hdec < 0)
return BOOK3S_INTERRUPT_HV_DECREMENTER;
+ WARN_ON_ONCE(vcpu->arch.shregs.msr & MSR_HV);
+ WARN_ON_ONCE(!(vcpu->arch.shregs.msr & MSR_ME));
+
start_timing(vcpu, &vcpu->arch.rm_entry);
+ vcpu->arch.ceded = 0;
+
if (vc->tb_offset) {
u64 new_tb = mftb() + vc->tb_offset;
mtspr(SPRN_TBU40, new_tb);
@@ -188,26 +193,6 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpc
mtspr(SPRN_HFSCR, vcpu->arch.hfscr);
- mtspr(SPRN_SPRG0, vcpu->arch.shregs.sprg0);
- mtspr(SPRN_SPRG1, vcpu->arch.shregs.sprg1);
- mtspr(SPRN_SPRG2, vcpu->arch.shregs.sprg2);
- mtspr(SPRN_SPRG3, vcpu->arch.shregs.sprg3);
-
- mtspr(SPRN_AMOR, ~0UL);
-
- switch_mmu_to_guest_radix(kvm, vcpu, lpcr);
-
- /*
- * P9 suppresses the HDEC exception when LPCR[HDICE] = 0,
- * so set guest LPCR (with HDICE) before writing HDEC.
- */
- mtspr(SPRN_HDEC, hdec);
-
- vcpu->arch.ceded = 0;
-
- WARN_ON_ONCE(vcpu->arch.shregs.msr & MSR_HV);
- WARN_ON_ONCE(!(vcpu->arch.shregs.msr & MSR_ME));
-
mtspr(SPRN_HSRR0, vcpu->arch.regs.nip);
mtspr(SPRN_HSRR1, (vcpu->arch.shregs.msr & ~MSR_HV) | MSR_ME);
@@ -226,6 +211,21 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpc
*/
mtspr(SPRN_HDSISR, HDSISR_CANARY);
+ mtspr(SPRN_SPRG0, vcpu->arch.shregs.sprg0);
+ mtspr(SPRN_SPRG1, vcpu->arch.shregs.sprg1);
+ mtspr(SPRN_SPRG2, vcpu->arch.shregs.sprg2);
+ mtspr(SPRN_SPRG3, vcpu->arch.shregs.sprg3);
+
+ mtspr(SPRN_AMOR, ~0UL);
+
+ switch_mmu_to_guest_radix(kvm, vcpu, lpcr);
+
+ /*
+ * P9 suppresses the HDEC exception when LPCR[HDICE] = 0,
+ * so set guest LPCR (with HDICE) before writing HDEC.
+ */
+ mtspr(SPRN_HDEC, hdec);
+
__mtmsrd(0, 1); /* clear RI */
mtspr(SPRN_DAR, vcpu->arch.shregs.dar);