Almost all logic is moved to C, by introducing a new in_guest mode for
the P9 path that branches very early in the KVM interrupt handler to
P9 exit code.
The main P9 entry and exit assembly is now only about 160 lines of low
level stack setup and register save/restore, plus a bad-interrupt
handler.
There are two motivations for this, the first is just make the code more
maintainable being in C. The second is to reduce the amount of code
running in a special KVM mode, "realmode". In quotes because with radix
it is no longer necessarily real-mode in the MMU, but it still has to be
treated specially because it may be in real-mode, and has various
important registers like PID, DEC, TB, etc set to guest. This is hostile
to the rest of Linux and can't use arbitrary kernel functionality or be
instrumented well.
This initial patch is a reasonably faithful conversion of the asm code,
but it does lack any loop to return quickly back into the guest without
switching out of realmode in the case of unimportant or easily handled
interrupts. As explained in previous changes, handling HV interrupts
in real mode is not so important for P9.
Use of Linux 64s interrupt entry code register conventions including
paca EX_ save areas are brought into the KVM code. There is no point
shuffling things into different paca save areas and making up a
different calling convention for KVM.
Signed-off-by: Nicholas Piggin <npiggin@xxxxxxxxx>
---
arch/powerpc/include/asm/asm-prototypes.h | 3 +-
arch/powerpc/include/asm/kvm_asm.h | 3 +-
arch/powerpc/include/asm/kvm_book3s_64.h | 8 +
arch/powerpc/include/asm/kvm_host.h | 7 +-
arch/powerpc/kernel/security.c | 5 +-
arch/powerpc/kvm/Makefile | 1 +
arch/powerpc/kvm/book3s_64_entry.S | 247 ++++++++++++++++++++++
arch/powerpc/kvm/book3s_hv.c | 9 +-
arch/powerpc/kvm/book3s_hv_interrupt.c | 218 +++++++++++++++++++
arch/powerpc/kvm/book3s_hv_rmhandlers.S | 125 +----------
10 files changed, 501 insertions(+), 125 deletions(-)
create mode 100644 arch/powerpc/kvm/book3s_hv_interrupt.c
diff --git a/arch/powerpc/include/asm/asm-prototypes.h b/arch/powerpc/include/asm/asm-prototypes.h
index 939f3c94c8f3..7c74c80ed994 100644
--- a/arch/powerpc/include/asm/asm-prototypes.h
+++ b/arch/powerpc/include/asm/asm-prototypes.h
@@ -122,6 +122,7 @@ extern s32 patch__call_flush_branch_caches3;
extern s32 patch__flush_count_cache_return;
extern s32 patch__flush_link_stack_return;
extern s32 patch__call_kvm_flush_link_stack;
+extern s32 patch__call_kvm_flush_link_stack_p9;
extern s32 patch__memset_nocache, patch__memcpy_nocache;
extern long flush_branch_caches;
@@ -142,7 +143,7 @@ void kvmhv_load_host_pmu(void);
void kvmhv_save_guest_pmu(struct kvm_vcpu *vcpu, bool pmu_in_use);
void kvmhv_load_guest_pmu(struct kvm_vcpu *vcpu);
-int __kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu);
+void kvmppc_p9_enter_guest(struct kvm_vcpu *vcpu);
long kvmppc_h_set_dabr(struct kvm_vcpu *vcpu, unsigned long dabr);
long kvmppc_h_set_xdabr(struct kvm_vcpu *vcpu, unsigned long dabr,
diff --git a/arch/powerpc/include/asm/kvm_asm.h b/arch/powerpc/include/asm/kvm_asm.h
index a3633560493b..b4f9996bd331 100644
--- a/arch/powerpc/include/asm/kvm_asm.h
+++ b/arch/powerpc/include/asm/kvm_asm.h
@@ -146,7 +146,8 @@
#define KVM_GUEST_MODE_GUEST 1
#define KVM_GUEST_MODE_SKIP 2
#define KVM_GUEST_MODE_GUEST_HV 3
-#define KVM_GUEST_MODE_HOST_HV 4
+#define KVM_GUEST_MODE_GUEST_HV_FAST 4 /* ISA v3.0 with host radix mode */
+#define KVM_GUEST_MODE_HOST_HV 5
#define KVM_INST_FETCH_FAILED -1
diff --git a/arch/powerpc/include/asm/kvm_book3s_64.h b/arch/powerpc/include/asm/kvm_book3s_64.h
index 9bb9bb370b53..c214bcffb441 100644
--- a/arch/powerpc/include/asm/kvm_book3s_64.h
+++ b/arch/powerpc/include/asm/kvm_book3s_64.h
@@ -153,9 +153,17 @@ static inline bool kvmhv_vcpu_is_radix(struct kvm_vcpu *vcpu)
return radix;
}
+int __kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu);
+
#define KVM_DEFAULT_HPT_ORDER 24 /* 16MB HPT by default */
#endif
+/*
+ * Invalid HDSISR value which is used to indicate when HW has not set the reg.
+ * Used to work around an errata.
+ */
+#define HDSISR_CANARY 0x7fff
+
/*
* We use a lock bit in HPTE dword 0 to synchronize updates and
* accesses to each HPTE, and another bit to indicate non-present
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index 05fb00d37609..fa0083345b11 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -690,7 +690,12 @@ struct kvm_vcpu_arch {
ulong fault_dar;
u32 fault_dsisr;
unsigned long intr_msr;
- ulong fault_gpa; /* guest real address of page fault (POWER9) */
+ /*
+ * POWER9 and later, fault_gpa contains the guest real address of page
+ * fault for a radix guest, or segment descriptor (equivalent to result
+ * from slbmfev of SLB entry that translated the EA) for hash guests.
+ */
+ ulong fault_gpa;
#endif
#ifdef CONFIG_BOOKE
diff --git a/arch/powerpc/kernel/security.c b/arch/powerpc/kernel/security.c
index e4e1a94ccf6a..3a607c11f20f 100644
--- a/arch/powerpc/kernel/security.c
+++ b/arch/powerpc/kernel/security.c
@@ -430,16 +430,19 @@ device_initcall(stf_barrier_debugfs_init);
static void update_branch_cache_flush(void)
{
- u32 *site;
+ u32 *site, __maybe_unused *site2;
#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
site = &patch__call_kvm_flush_link_stack;
+ site2 = &patch__call_kvm_flush_link_stack_p9;
// This controls the branch from guest_exit_cont to kvm_flush_link_stack
if (link_stack_flush_type == BRANCH_CACHE_FLUSH_NONE) {
patch_instruction_site(site, ppc_inst(PPC_INST_NOP));
+ patch_instruction_site(site2, ppc_inst(PPC_INST_NOP));
} else {
// Could use HW flush, but that could also flush count cache
patch_branch_site(site, (u64)&kvm_flush_link_stack, BRANCH_SET_LINK);
+ patch_branch_site(site2, (u64)&kvm_flush_link_stack, BRANCH_SET_LINK);
}
#endif
diff --git a/arch/powerpc/kvm/Makefile b/arch/powerpc/kvm/Makefile
index cdd119028f64..ca7c86aa9360 100644
--- a/arch/powerpc/kvm/Makefile
+++ b/arch/powerpc/kvm/Makefile
@@ -88,6 +88,7 @@ kvm-book3s_64-builtin-tm-objs-$(CONFIG_PPC_TRANSACTIONAL_MEM) += \
ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
kvm-book3s_64-builtin-objs-$(CONFIG_KVM_BOOK3S_64_HANDLER) += \
+ book3s_hv_interrupt.o \
book3s_hv_hmi.o \
book3s_hv_rmhandlers.o \
book3s_hv_rm_mmu.o \
diff --git a/arch/powerpc/kvm/book3s_64_entry.S b/arch/powerpc/kvm/book3s_64_entry.S
index 0c79c89c6a4b..d98ad580fd98 100644
--- a/arch/powerpc/kvm/book3s_64_entry.S
+++ b/arch/powerpc/kvm/book3s_64_entry.S
@@ -1,11 +1,16 @@
/* SPDX-License-Identifier: GPL-2.0-only */
#include <asm/asm-offsets.h>
#include <asm/cache.h>
+#include <asm/code-patching-asm.h>
#include <asm/exception-64s.h>
+#include <asm/export.h>
#include <asm/kvm_asm.h>
#include <asm/kvm_book3s_asm.h>
+#include <asm/mmu.h>
#include <asm/ppc_asm.h>
+#include <asm/ptrace.h>
#include <asm/reg.h>
+#include <asm/ultravisor-api.h>
/*
* These are branched to from interrupt handlers in exception-64s.S which set
@@ -29,10 +34,15 @@
.global kvmppc_hcall
.balign IFETCH_ALIGN_BYTES
kvmppc_hcall:
+ lbz r10,HSTATE_IN_GUEST(r13)
+ cmpwi r10,KVM_GUEST_MODE_GUEST_HV_FAST
+ beq kvmppc_p9_exit_hcall
ld r10,PACA_EXGEN+EX_R13(r13)
SET_SCRATCH0(r10)
li r10,0xc00
/* Now we look like kvmppc_interrupt */
+ li r11,PACA_EXGEN
+ b 1f
/*
* KVM interrupt entry occurs after GEN_INT_ENTRY runs, and follows that
@@ -53,6 +63,12 @@ kvmppc_hcall:
.global kvmppc_interrupt
.balign IFETCH_ALIGN_BYTES
kvmppc_interrupt:
+ std r10,HSTATE_SCRATCH0(r13)
+ lbz r10,HSTATE_IN_GUEST(r13)
+ cmpwi r10,KVM_GUEST_MODE_GUEST_HV_FAST
+ beq kvmppc_p9_exit_interrupt
+ ld r10,HSTATE_SCRATCH0(r13)
+ lbz r11,HSTATE_IN_GUEST(r13)
li r11,PACA_EXGEN
cmpdi r10,0x200
bgt+ 1f
@@ -154,3 +170,234 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
GET_SCRATCH0(r13)
HRFI_TO_KERNEL
#endif
+
+/* Stack frame offsets for kvmppc_hv_entry */
+#define SFS (144 + STACK_FRAME_MIN_SIZE)
+#define STACK_SLOT_NVGPRS (SFS - 144) /* 18 gprs */
+
+/*
+ * 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 both the host and guest are radix, and threads
+ * are set to "indepdent mode".
+ */
+.balign IFETCH_ALIGN_BYTES
+_GLOBAL(kvmppc_p9_enter_guest)
+EXPORT_SYMBOL_GPL(kvmppc_p9_enter_guest)
+ mflr r0
+ std r0,PPC_LR_STKOFF(r1)
+ stdu r1,-SFS(r1)
+
+ std r1,HSTATE_HOST_R1(r13)
+
+ mfcr r4
+ stw r4,SFS+8(r1)
+
+ reg = 14
+ .rept 18
+ std reg,STACK_SLOT_NVGPRS + ((reg - 14) * 8)(r1)
+ reg = reg + 1
+ .endr
+
+ ld r4,VCPU_LR(r3)
+ mtlr r4
+ ld r4,VCPU_CTR(r3)
+ mtctr r4
+ ld r4,VCPU_XER(r3)
+ mtspr SPRN_XER,r4
+
+ ld r1,VCPU_CR(r3)
+
+BEGIN_FTR_SECTION
+ ld r4,VCPU_CFAR(r3)
+ mtspr SPRN_CFAR,r4
+END_FTR_SECTION_IFSET(CPU_FTR_CFAR)
+BEGIN_FTR_SECTION
+ ld r4,VCPU_PPR(r3)
+ mtspr SPRN_PPR,r4
+END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
+
+ reg = 4
+ .rept 28
+ ld reg,__VCPU_GPR(reg)(r3)
+ reg = reg + 1
+ .endr
+
+ ld r4,VCPU_KVM(r3)
+ lbz r4,KVM_SECURE_GUEST(r4)
