[PATCH 1/2] powerpc: Fix definition of PCR bits to work with old binutils

Subsystems: linux for powerpc (32-bit and 64-bit), the rest

STALE2499d LANDED

Landed in mainline as c6fadabb2868 on 2019-09-20.

4 messages, 3 authors, 2019-09-30 · open the first message on its own page

[PATCH 1/2] powerpc: Fix definition of PCR bits to work with old binutils

From: Alistair Popple <hidden>
Date: 2019-09-17 00:48:12

Commit 388cc6e133132 ("KVM: PPC: Book3S HV: Support POWER6
compatibility mode on POWER7") introduced new macros defining the PCR
bits. When used from assembly files these definitions lead to build
errors using older versions of binutils that don't support the 'ul'
suffix. This fixes the build errors by updating the definitions to use
the __MASK() macro which selects the appropriate suffix.

Signed-off-by: Alistair Popple <redacted>
---
 arch/powerpc/include/asm/reg.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index 10caa145f98b..a18c366aa0d7 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h

@@ -472,9 +472,9 @@
 #define   HMER_DEBUG_TRIG	(1ul << (63 - 17)) /* Debug trigger */
 #define	SPRN_HMEER	0x151	/* Hyp maintenance exception enable reg */
 #define SPRN_PCR	0x152	/* Processor compatibility register */
-#define   PCR_VEC_DIS	(1ul << (63-0))	/* Vec. disable (bit NA since POWER8) */
-#define   PCR_VSX_DIS	(1ul << (63-1))	/* VSX disable (bit NA since POWER8) */
-#define   PCR_TM_DIS	(1ul << (63-2))	/* Trans. memory disable (POWER8) */
+#define   PCR_VEC_DIS	(__MASK(63-0))	/* Vec. disable (bit NA since POWER8) */
+#define   PCR_VSX_DIS	(__MASK(63-1))	/* VSX disable (bit NA since POWER8) */
+#define   PCR_TM_DIS	(__MASK(63-2))	/* Trans. memory disable (POWER8) */
 /*
  * These bits are used in the function kvmppc_set_arch_compat() to specify and
  * determine both the compatibility level which we want to emulate and the

-- 
2.20.1

[PATCH 2/2] PPC: Set reserved PCR bits

From: Alistair Popple <hidden>
Date: 2019-09-17 00:50:06

From: Jordan Niethe <redacted>

Currently the reserved bits of the Processor Compatibility Register
(PCR) are cleared as per the Programming Note in Section 1.3.3 of
version 3.0B of the Power ISA. This causes all new architecture
features to be made available when running on newer processors with
new architecture features added to the PCR as bits must be set to
disable a given feature.

For example to disable new features added as part of Version 2.07 of
the ISA the corresponding bit in the PCR needs to be set.

As new processor features generally require explicit kernel support
they should be disabled until such support is implemented. Therefore
kernels should set all unknown/reserved bits in the PCR such that any
new architecture features which the kernel does not currently know
about get disabled.

An update is planned to the ISA to clarify that the PCR is an
exception to the Programming Note on reserved bits in Section 1.3.3.

Signed-off-by: Alistair Popple <redacted>
Signed-off-by: Jordan Niethe <redacted>
Tested-by: Joel Stanley <joel@jms.id.au>
---
 arch/powerpc/include/asm/reg.h          |  3 +++
 arch/powerpc/kernel/cpu_setup_power.S   |  6 ++++++
 arch/powerpc/kernel/dt_cpu_ftrs.c       |  3 ++-
 arch/powerpc/kvm/book3s_hv.c            | 11 +++++++----
 arch/powerpc/kvm/book3s_hv_nested.c     |  6 +++---
 arch/powerpc/kvm/book3s_hv_rmhandlers.S | 10 ++++++----
 6 files changed, 27 insertions(+), 12 deletions(-)

diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index a18c366aa0d7..f2423496237f 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h

@@ -475,6 +475,7 @@
 #define   PCR_VEC_DIS	(__MASK(63-0))	/* Vec. disable (bit NA since POWER8) */
 #define   PCR_VSX_DIS	(__MASK(63-1))	/* VSX disable (bit NA since POWER8) */
 #define   PCR_TM_DIS	(__MASK(63-2))	/* Trans. memory disable (POWER8) */
+#define   PCR_HIGH_BITS	(PCR_VEC_DIS | PCR_VSX_DIS | PCR_TM_DIS)
 /*
  * These bits are used in the function kvmppc_set_arch_compat() to specify and
  * determine both the compatibility level which we want to emulate and the

@@ -483,6 +484,8 @@
 #define   PCR_ARCH_207	0x8		/* Architecture 2.07 */
 #define   PCR_ARCH_206	0x4		/* Architecture 2.06 */
 #define   PCR_ARCH_205	0x2		/* Architecture 2.05 */
+#define   PCR_LOW_BITS	(PCR_ARCH_207 | PCR_ARCH_206 | PCR_ARCH_205)
+#define   PCR_MASK	~(PCR_HIGH_BITS | PCR_LOW_BITS)	/* PCR Reserved Bits */
 #define	SPRN_HEIR	0x153	/* Hypervisor Emulated Instruction Register */
 #define SPRN_TLBINDEXR	0x154	/* P7 TLB control register */
 #define SPRN_TLBVPNR	0x155	/* P7 TLB control register */

diff --git a/arch/powerpc/kernel/cpu_setup_power.S b/arch/powerpc/kernel/cpu_setup_power.S
index 3239a9fe6c1c..a460298c7ddb 100644
--- a/arch/powerpc/kernel/cpu_setup_power.S
+++ b/arch/powerpc/kernel/cpu_setup_power.S

@@ -23,6 +23,7 @@ _GLOBAL(__setup_cpu_power7)
 	beqlr
 	li	r0,0
 	mtspr	SPRN_LPID,r0
+	LOAD_REG_IMMEDIATE(r0, PCR_MASK)
 	mtspr	SPRN_PCR,r0
 	mfspr	r3,SPRN_LPCR
 	li	r4,(LPCR_LPES1 >> LPCR_LPES_SH)

@@ -37,6 +38,7 @@ _GLOBAL(__restore_cpu_power7)
 	beqlr
 	li	r0,0
 	mtspr	SPRN_LPID,r0
+	LOAD_REG_IMMEDIATE(r0, PCR_MASK)
 	mtspr	SPRN_PCR,r0
 	mfspr	r3,SPRN_LPCR
 	li	r4,(LPCR_LPES1 >> LPCR_LPES_SH)

@@ -54,6 +56,7 @@ _GLOBAL(__setup_cpu_power8)
 	beqlr
 	li	r0,0
 	mtspr	SPRN_LPID,r0
+	LOAD_REG_IMMEDIATE(r0, PCR_MASK)
 	mtspr	SPRN_PCR,r0
 	mfspr	r3,SPRN_LPCR
 	ori	r3, r3, LPCR_PECEDH

@@ -76,6 +79,7 @@ _GLOBAL(__restore_cpu_power8)
 	beqlr
 	li	r0,0
 	mtspr	SPRN_LPID,r0
+	LOAD_REG_IMMEDIATE(r0, PCR_MASK)
 	mtspr	SPRN_PCR,r0
 	mfspr   r3,SPRN_LPCR
 	ori	r3, r3, LPCR_PECEDH

@@ -98,6 +102,7 @@ _GLOBAL(__setup_cpu_power9)
 	mtspr	SPRN_PSSCR,r0
 	mtspr	SPRN_LPID,r0
 	mtspr	SPRN_PID,r0
+	LOAD_REG_IMMEDIATE(r0, PCR_MASK)
 	mtspr	SPRN_PCR,r0
 	mfspr	r3,SPRN_LPCR
 	LOAD_REG_IMMEDIATE(r4, LPCR_PECEDH | LPCR_PECE_HVEE | LPCR_HVICE  | LPCR_HEIC)

@@ -123,6 +128,7 @@ _GLOBAL(__restore_cpu_power9)
 	mtspr	SPRN_PSSCR,r0
 	mtspr	SPRN_LPID,r0
 	mtspr	SPRN_PID,r0
+	LOAD_REG_IMMEDIATE(r0, PCR_MASK)
 	mtspr	SPRN_PCR,r0
 	mfspr   r3,SPRN_LPCR
 	LOAD_REG_IMMEDIATE(r4, LPCR_PECEDH | LPCR_PECE_HVEE | LPCR_HVICE | LPCR_HEIC)

diff --git a/arch/powerpc/kernel/dt_cpu_ftrs.c b/arch/powerpc/kernel/dt_cpu_ftrs.c
index bd95318d2202..bceee2fde885 100644
--- a/arch/powerpc/kernel/dt_cpu_ftrs.c
+++ b/arch/powerpc/kernel/dt_cpu_ftrs.c

@@ -101,7 +101,7 @@ static void __restore_cpu_cpufeatures(void)
 	if (hv_mode) {
 		mtspr(SPRN_LPID, 0);
 		mtspr(SPRN_HFSCR, system_registers.hfscr);
-		mtspr(SPRN_PCR, 0);
+		mtspr(SPRN_PCR, PCR_MASK);
 	}
 	mtspr(SPRN_FSCR, system_registers.fscr);

@@ -144,6 +144,7 @@ static void __init cpufeatures_setup_cpu(void)
 		mtspr(SPRN_HFSCR, 0);
 	}
 	mtspr(SPRN_FSCR, 0);
+	mtspr(SPRN_PCR, PCR_MASK);
 
 	/*
 	 * LPCR does not get cleared, to match behaviour with secondaries

diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index cde3f5a4b3e4..7a133c3aebe6 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c

@@ -401,8 +401,11 @@ static int kvmppc_set_arch_compat(struct kvm_vcpu *vcpu, u32 arch_compat)
 
 	spin_lock(&vc->lock);
 	vc->arch_compat = arch_compat;
-	/* Set all PCR bits for which guest_pcr_bit <= bit < host_pcr_bit */
-	vc->pcr = host_pcr_bit - guest_pcr_bit;
+	/*
+	 * Set all PCR bits for which guest_pcr_bit <= bit < host_pcr_bit
+	 * Also set all reserved PCR bits
+	 */
+	vc->pcr = (host_pcr_bit - guest_pcr_bit) | PCR_MASK;
 	spin_unlock(&vc->lock);
 
 	return 0;

@@ -3398,7 +3401,7 @@ static int kvmhv_load_hv_regs_and_go(struct kvm_vcpu *vcpu, u64 time_limit,
 	}
 
 	if (vc->pcr)
-		mtspr(SPRN_PCR, vc->pcr);
+		mtspr(SPRN_PCR, vc->pcr | PCR_MASK);
 	mtspr(SPRN_DPDES, vc->dpdes);
 	mtspr(SPRN_VTB, vc->vtb);

@@ -3478,7 +3481,7 @@ static int kvmhv_load_hv_regs_and_go(struct kvm_vcpu *vcpu, u64 time_limit,
 	vc->vtb = mfspr(SPRN_VTB);
 	mtspr(SPRN_DPDES, 0);
 	if (vc->pcr)
-		mtspr(SPRN_PCR, 0);
+		mtspr(SPRN_PCR, PCR_MASK);
 
 	if (vc->tb_offset_applied) {
 		u64 new_tb = mftb() - vc->tb_offset_applied;

diff --git a/arch/powerpc/kvm/book3s_hv_nested.c b/arch/powerpc/kvm/book3s_hv_nested.c
index 735e0ac6f5b2..e916522c5c39 100644
--- a/arch/powerpc/kvm/book3s_hv_nested.c
+++ b/arch/powerpc/kvm/book3s_hv_nested.c

@@ -29,7 +29,7 @@ void kvmhv_save_hv_regs(struct kvm_vcpu *vcpu, struct hv_guest_state *hr)
 {
 	struct kvmppc_vcore *vc = vcpu->arch.vcore;
 
-	hr->pcr = vc->pcr;
+	hr->pcr = vc->pcr | PCR_MASK;
 	hr->dpdes = vc->dpdes;
 	hr->hfscr = vcpu->arch.hfscr;
 	hr->tb_offset = vc->tb_offset;

@@ -65,7 +65,7 @@ static void byteswap_hv_regs(struct hv_guest_state *hr)
 	hr->lpid = swab32(hr->lpid);
 	hr->vcpu_token = swab32(hr->vcpu_token);
 	hr->lpcr = swab64(hr->lpcr);
-	hr->pcr = swab64(hr->pcr);
+	hr->pcr = swab64(hr->pcr) | PCR_MASK;
 	hr->amor = swab64(hr->amor);
 	hr->dpdes = swab64(hr->dpdes);
 	hr->hfscr = swab64(hr->hfscr);

@@ -148,7 +148,7 @@ static void restore_hv_regs(struct kvm_vcpu *vcpu, struct hv_guest_state *hr)
 {
 	struct kvmppc_vcore *vc = vcpu->arch.vcore;
 
-	vc->pcr = hr->pcr;
+	vc->pcr = hr->pcr | PCR_MASK;
 	vc->dpdes = hr->dpdes;
 	vcpu->arch.hfscr = hr->hfscr;
 	vcpu->arch.dawr = hr->dawr0;

diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index 337e64468d78..f21dee7a1757 100644
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S

@@ -643,8 +643,10 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_300)
 
 	/* Load guest PCR value to select appropriate compat mode */
 37:	ld	r7, VCORE_PCR(r5)
-	cmpdi	r7, 0
+	LOAD_REG_IMMEDIATE(r6, PCR_MASK)
+	cmpld	r7, r6
 	beq	38f
+	or	r7, r7, r6
 	mtspr	SPRN_PCR, r7
 38:

@@ -1884,10 +1886,10 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)
 
 	/* Reset PCR */
 	ld	r0, VCORE_PCR(r5)
-	cmpdi	r0, 0
+	LOAD_REG_IMMEDIATE(r6, PCR_MASK)
+	cmpld	r0, r6
 	beq	18f
-	li	r0, 0
-	mtspr	SPRN_PCR, r0
+	mtspr	SPRN_PCR, r6
 18:
 	/* Signal secondary CPUs to continue */
 	stb	r0,VCORE_IN_GUEST(r5)

-- 
2.20.1

Re: [PATCH 1/2] powerpc: Fix definition of PCR bits to work with old binutils

From: Michael Ellerman <hidden>
Date: 2019-09-25 11:16:20

On Tue, 2019-09-17 at 00:46:04 UTC, Alistair Popple wrote:

Commit 388cc6e133132 ("KVM: PPC: Book3S HV: Support POWER6
compatibility mode on POWER7") introduced new macros defining the PCR
bits. When used from assembly files these definitions lead to build
errors using older versions of binutils that don't support the 'ul'
suffix. This fixes the build errors by updating the definitions to use
the __MASK() macro which selects the appropriate suffix.

Signed-off-by: Alistair Popple <redacted>

Series applied to powerpc fixes, thanks.

https://git.kernel.org/powerpc/c/c6fadabb2868f817299ddb338ac15885e25d12d2

cheers

Re: [PATCH 1/2] powerpc: Fix definition of PCR bits to work with old binutils

From: Alexey Kardashevskiy <hidden>
Date: 2019-09-30 09:57:55


On 25/09/2019 21:05, Michael Ellerman wrote:

On Tue, 2019-09-17 at 00:46:04 UTC, Alistair Popple wrote:

quoted

Commit 388cc6e133132 ("KVM: PPC: Book3S HV: Support POWER6
compatibility mode on POWER7") introduced new macros defining the PCR
bits. When used from assembly files these definitions lead to build
errors using older versions of binutils that don't support the 'ul'
suffix. This fixes the build errors by updating the definitions to use
the __MASK() macro which selects the appropriate suffix.

Signed-off-by: Alistair Popple <redacted>

Series applied to powerpc fixes, thanks.

https://git.kernel.org/powerpc/c/c6fadabb2868f817299ddb338ac15885e25d12d2


It breaks KVM on POWER8's garrison:
===
KVM: CPU 1 seems to be stuck
KVM: CPU 2 seems to be stuck
KVM: CPU 3 seems to be stuck
KVM: CPU 4 seems to be stuck
KVM: CPU 5 seems to be stuck
KVM: CPU 6 seems to be stuck
KVM: CPU 7 seems to be stuck
===
in a loop.


Run as: "taskset -c 0 qemu-system-ppc64 -smp 8,threads=8"


The patch below fixes it and I have no idea why. 0x1ffffffffffffff1 is the PCR after the mask applied to it.

diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 709cf1fd4cf4..9df9865b2e5b 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c

@@ -406,6 +406,7 @@ static int kvmppc_set_arch_compat(struct kvm_vcpu *vcpu, u32 arch_compat)
         * Also set all reserved PCR bits
         */
        vc->pcr = (host_pcr_bit - guest_pcr_bit) | PCR_MASK;
+       vc->pcr &= 0xffffffffffffff00UL;
        spin_unlock(&vc->lock);

        return 0;

@@ -3413,7 +3414,7 @@ static int kvmhv_load_hv_regs_and_go(struct kvm_vcpu *vcpu, u64 time_limit,
        }

        if (vc->pcr)
-               mtspr(SPRN_PCR, vc->pcr | PCR_MASK);
+               mtspr(SPRN_PCR, vc->pcr);
        mtspr(SPRN_DPDES, vc->dpdes);
        mtspr(SPRN_VTB, vc->vtb);

-- 
Alexey

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