2020-07-23 10:23:12

by Ravi Bangoria

[permalink] [raw]
Subject: [PATCH 2/7] powerpc/watchpoint/kvm: Add infrastructure to support 2nd DAWR

kvm code assumes single DAWR everywhere. Add code to support 2nd DAWR.
DAWR is a hypervisor resource and thus H_SET_MODE hcall is used to set/
unset it. Introduce new case H_SET_MODE_RESOURCE_SET_DAWR1 for 2nd DAWR.
Also, kvm will support 2nd DAWR only if CPU_FTR_DAWR1 is set.

Signed-off-by: Ravi Bangoria <[email protected]>
---
Documentation/virt/kvm/api.rst | 2 ++
arch/powerpc/include/asm/hvcall.h | 2 ++
arch/powerpc/include/asm/kvm_host.h | 2 ++
arch/powerpc/include/uapi/asm/kvm.h | 4 +++
arch/powerpc/kernel/asm-offsets.c | 2 ++
arch/powerpc/kvm/book3s_hv.c | 41 +++++++++++++++++++++++
arch/powerpc/kvm/book3s_hv_nested.c | 7 ++++
arch/powerpc/kvm/book3s_hv_rmhandlers.S | 23 +++++++++++++
tools/arch/powerpc/include/uapi/asm/kvm.h | 4 +++
9 files changed, 87 insertions(+)

diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index 4dc18fe6a2bf..7b1d16c2ad24 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -2242,6 +2242,8 @@ registers, find a list below:
PPC KVM_REG_PPC_PSSCR 64
PPC KVM_REG_PPC_DEC_EXPIRY 64
PPC KVM_REG_PPC_PTCR 64
+ PPC KVM_REG_PPC_DAWR1 64
+ PPC KVM_REG_PPC_DAWRX1 64
PPC KVM_REG_PPC_TM_GPR0 64
...
PPC KVM_REG_PPC_TM_GPR31 64
diff --git a/arch/powerpc/include/asm/hvcall.h b/arch/powerpc/include/asm/hvcall.h
index 33793444144c..03f401d7be41 100644
--- a/arch/powerpc/include/asm/hvcall.h
+++ b/arch/powerpc/include/asm/hvcall.h
@@ -538,6 +538,8 @@ struct hv_guest_state {
s64 tb_offset;
u64 dawr0;
u64 dawrx0;
+ u64 dawr1;
+ u64 dawrx1;
u64 ciabr;
u64 hdec_expiry;
u64 purr;
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index 9aa3854f0e1e..bda839edd5fe 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -584,6 +584,8 @@ struct kvm_vcpu_arch {
ulong dabr;
ulong dawr0;
ulong dawrx0;
+ ulong dawr1;
+ ulong dawrx1;
ulong ciabr;
ulong cfar;
ulong ppr;
diff --git a/arch/powerpc/include/uapi/asm/kvm.h b/arch/powerpc/include/uapi/asm/kvm.h
index 38d61b73f5ed..c5c0f128b46f 100644
--- a/arch/powerpc/include/uapi/asm/kvm.h
+++ b/arch/powerpc/include/uapi/asm/kvm.h
@@ -640,6 +640,10 @@ struct kvm_ppc_cpu_char {
#define KVM_REG_PPC_ONLINE (KVM_REG_PPC | KVM_REG_SIZE_U32 | 0xbf)
#define KVM_REG_PPC_PTCR (KVM_REG_PPC | KVM_REG_SIZE_U64 | 0xc0)

+/* POWER10 registers. */
+#define KVM_REG_PPC_DAWR1 (KVM_REG_PPC | KVM_REG_SIZE_U64 | 0xc1)
+#define KVM_REG_PPC_DAWRX1 (KVM_REG_PPC | KVM_REG_SIZE_U64 | 0xc2)
+
/* Transactional Memory checkpointed state:
* This is all GPRs, all VSX regs and a subset of SPRs
*/
diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
index e76bffe348e1..ef2c0f3f5a7b 100644
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -549,6 +549,8 @@ int main(void)
OFFSET(VCPU_DABRX, kvm_vcpu, arch.dabrx);
OFFSET(VCPU_DAWR0, kvm_vcpu, arch.dawr0);
OFFSET(VCPU_DAWRX0, kvm_vcpu, arch.dawrx0);
+ OFFSET(VCPU_DAWR1, kvm_vcpu, arch.dawr1);
+ OFFSET(VCPU_DAWRX1, kvm_vcpu, arch.dawrx1);
OFFSET(VCPU_CIABR, kvm_vcpu, arch.ciabr);
OFFSET(VCPU_HFLAGS, kvm_vcpu, arch.hflags);
OFFSET(VCPU_DEC, kvm_vcpu, arch.dec);
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 28200e4f5d27..24575520b2ea 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -781,6 +781,20 @@ static int kvmppc_h_set_mode(struct kvm_vcpu *vcpu, unsigned long mflags,
vcpu->arch.dawr0 = value1;
vcpu->arch.dawrx0 = value2;
return H_SUCCESS;
+ case H_SET_MODE_RESOURCE_SET_DAWR1:
+ if (!kvmppc_power8_compatible(vcpu))
+ return H_P2;
+ if (!ppc_breakpoint_available())
+ return H_P2;
+ if (!cpu_has_feature(CPU_FTR_DAWR1))
+ return H_P2;
+ if (mflags)
+ return H_UNSUPPORTED_FLAG_START;
+ if (value2 & DABRX_HYP)
+ return H_P4;
+ vcpu->arch.dawr1 = value1;
+ vcpu->arch.dawrx1 = value2;
+ return H_SUCCESS;
case H_SET_MODE_RESOURCE_ADDR_TRANS_MODE:
/* KVM does not support mflags=2 (AIL=2) */
if (mflags != 0 && mflags != 3)
@@ -1730,6 +1744,12 @@ static int kvmppc_get_one_reg_hv(struct kvm_vcpu *vcpu, u64 id,
case KVM_REG_PPC_DAWRX0:
*val = get_reg_val(id, vcpu->arch.dawrx0);
break;
+ case KVM_REG_PPC_DAWR1:
+ *val = get_reg_val(id, vcpu->arch.dawr1);
+ break;
+ case KVM_REG_PPC_DAWRX1:
+ *val = get_reg_val(id, vcpu->arch.dawrx1);
+ break;
case KVM_REG_PPC_CIABR:
*val = get_reg_val(id, vcpu->arch.ciabr);
break;
@@ -1944,6 +1964,12 @@ static int kvmppc_set_one_reg_hv(struct kvm_vcpu *vcpu, u64 id,
case KVM_REG_PPC_DAWRX0:
vcpu->arch.dawrx0 = set_reg_val(id, *val) & ~DAWRX_HYP;
break;
+ case KVM_REG_PPC_DAWR1:
+ vcpu->arch.dawr1 = set_reg_val(id, *val);
+ break;
+ case KVM_REG_PPC_DAWRX1:
+ vcpu->arch.dawrx1 = set_reg_val(id, *val) & ~DAWRX_HYP;
+ break;
case KVM_REG_PPC_CIABR:
vcpu->arch.ciabr = set_reg_val(id, *val);
/* Don't allow setting breakpoints in hypervisor code */
@@ -3401,6 +3427,13 @@ static int kvmhv_load_hv_regs_and_go(struct kvm_vcpu *vcpu, u64 time_limit,
unsigned long host_dawrx0 = mfspr(SPRN_DAWRX0);
unsigned long host_psscr = mfspr(SPRN_PSSCR);
unsigned long host_pidr = mfspr(SPRN_PID);
+ unsigned long host_dawr1 = 0;
+ unsigned long host_dawrx1 = 0;
+
+ if (cpu_has_feature(CPU_FTR_DAWR1)) {
+ host_dawr1 = mfspr(SPRN_DAWR1);
+ host_dawrx1 = mfspr(SPRN_DAWRX1);
+ }

hdec = time_limit - mftb();
if (hdec < 0)
@@ -3429,6 +3462,10 @@ static int kvmhv_load_hv_regs_and_go(struct kvm_vcpu *vcpu, u64 time_limit,
if (dawr_enabled()) {
mtspr(SPRN_DAWR0, vcpu->arch.dawr0);
mtspr(SPRN_DAWRX0, vcpu->arch.dawrx0);
+ if (cpu_has_feature(CPU_FTR_DAWR1)) {
+ mtspr(SPRN_DAWR1, vcpu->arch.dawr1);
+ mtspr(SPRN_DAWRX1, vcpu->arch.dawrx1);
+ }
}
mtspr(SPRN_CIABR, vcpu->arch.ciabr);
mtspr(SPRN_IC, vcpu->arch.ic);
@@ -3482,6 +3519,10 @@ static int kvmhv_load_hv_regs_and_go(struct kvm_vcpu *vcpu, u64 time_limit,
mtspr(SPRN_CIABR, host_ciabr);
mtspr(SPRN_DAWR0, host_dawr0);
mtspr(SPRN_DAWRX0, host_dawrx0);
+ if (cpu_has_feature(CPU_FTR_DAWR1)) {
+ mtspr(SPRN_DAWR1, host_dawr1);
+ mtspr(SPRN_DAWRX1, host_dawrx1);
+ }
mtspr(SPRN_PID, host_pidr);

/*
diff --git a/arch/powerpc/kvm/book3s_hv_nested.c b/arch/powerpc/kvm/book3s_hv_nested.c
index 629f74edab22..03a3c7c5dc28 100644
--- a/arch/powerpc/kvm/book3s_hv_nested.c
+++ b/arch/powerpc/kvm/book3s_hv_nested.c
@@ -35,6 +35,8 @@ void kvmhv_save_hv_regs(struct kvm_vcpu *vcpu, struct hv_guest_state *hr)
hr->tb_offset = vc->tb_offset;
hr->dawr0 = vcpu->arch.dawr0;
hr->dawrx0 = vcpu->arch.dawrx0;
+ hr->dawr1 = vcpu->arch.dawr1;
+ hr->dawrx1 = vcpu->arch.dawrx1;
hr->ciabr = vcpu->arch.ciabr;
hr->purr = vcpu->arch.purr;
hr->spurr = vcpu->arch.spurr;
@@ -72,6 +74,8 @@ static void byteswap_hv_regs(struct hv_guest_state *hr)
hr->tb_offset = swab64(hr->tb_offset);
hr->dawr0 = swab64(hr->dawr0);
hr->dawrx0 = swab64(hr->dawrx0);
+ hr->dawr1 = swab64(hr->dawr1);
+ hr->dawrx1 = swab64(hr->dawrx1);
hr->ciabr = swab64(hr->ciabr);
hr->hdec_expiry = swab64(hr->hdec_expiry);
hr->purr = swab64(hr->purr);
@@ -138,6 +142,7 @@ static void sanitise_hv_regs(struct kvm_vcpu *vcpu, struct hv_guest_state *hr)

/* Don't let data address watchpoint match in hypervisor state */
hr->dawrx0 &= ~DAWRX_HYP;
+ hr->dawrx1 &= ~DAWRX_HYP;

/* Don't let completed instruction address breakpt match in HV state */
if ((hr->ciabr & CIABR_PRIV) == CIABR_PRIV_HYPER)
@@ -153,6 +158,8 @@ static void restore_hv_regs(struct kvm_vcpu *vcpu, struct hv_guest_state *hr)
vcpu->arch.hfscr = hr->hfscr;
vcpu->arch.dawr0 = hr->dawr0;
vcpu->arch.dawrx0 = hr->dawrx0;
+ vcpu->arch.dawr1 = hr->dawr1;
+ vcpu->arch.dawrx1 = hr->dawrx1;
vcpu->arch.ciabr = hr->ciabr;
vcpu->arch.purr = hr->purr;
vcpu->arch.spurr = hr->spurr;
diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index e562a9acbc2a..2006ec149532 100644
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -57,6 +57,8 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_300)
#define STACK_SLOT_HFSCR (SFS-72)
#define STACK_SLOT_AMR (SFS-80)
#define STACK_SLOT_UAMOR (SFS-88)
+#define STACK_SLOT_DAWR1 (SFS-96)
+#define STACK_SLOT_DAWRX1 (SFS-104)
/* the following is used by the P9 short path */
#define STACK_SLOT_NVGPRS (SFS-152) /* 18 gprs */

@@ -715,6 +717,12 @@ BEGIN_FTR_SECTION
std r7, STACK_SLOT_DAWRX0(r1)
std r8, STACK_SLOT_IAMR(r1)
END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)
+BEGIN_FTR_SECTION
+ mfspr r6, SPRN_DAWR1
+ mfspr r7, SPRN_DAWRX1
+ std r6, STACK_SLOT_DAWR1(r1)
+ std r7, STACK_SLOT_DAWRX1(r1)
+END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S | CPU_FTR_DAWR1)

mfspr r5, SPRN_AMR
std r5, STACK_SLOT_AMR(r1)
@@ -805,6 +813,12 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_207S)
ld r6, VCPU_DAWRX0(r4)
mtspr SPRN_DAWR0, r5
mtspr SPRN_DAWRX0, r6
+BEGIN_FTR_SECTION
+ ld r5, VCPU_DAWR1(r4)
+ ld r6, VCPU_DAWRX1(r4)
+ mtspr SPRN_DAWR1, r5
+ mtspr SPRN_DAWRX1, r6
+END_FTR_SECTION_IFSET(CPU_FTR_DAWR1)
1:
ld r7, VCPU_CIABR(r4)
ld r8, VCPU_TAR(r4)
@@ -1769,6 +1783,12 @@ BEGIN_FTR_SECTION
mtspr SPRN_DAWR0, r6
mtspr SPRN_DAWRX0, r7
END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)
+BEGIN_FTR_SECTION
+ ld r6, STACK_SLOT_DAWR1(r1)
+ ld r7, STACK_SLOT_DAWRX1(r1)
+ mtspr SPRN_DAWR1, r6
+ mtspr SPRN_DAWRX1, r7
+END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S | CPU_FTR_DAWR1)
BEGIN_FTR_SECTION
ld r5, STACK_SLOT_TID(r1)
ld r6, STACK_SLOT_PSSCR(r1)
@@ -3335,6 +3355,9 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_300)
mtspr SPRN_IAMR, r0
mtspr SPRN_CIABR, r0
mtspr SPRN_DAWRX0, r0
+BEGIN_FTR_SECTION
+ mtspr SPRN_DAWRX1, r0
+END_FTR_SECTION_IFSET(CPU_FTR_DAWR1)

BEGIN_MMU_FTR_SECTION
b 4f
diff --git a/tools/arch/powerpc/include/uapi/asm/kvm.h b/tools/arch/powerpc/include/uapi/asm/kvm.h
index 38d61b73f5ed..c5c0f128b46f 100644
--- a/tools/arch/powerpc/include/uapi/asm/kvm.h
+++ b/tools/arch/powerpc/include/uapi/asm/kvm.h
@@ -640,6 +640,10 @@ struct kvm_ppc_cpu_char {
#define KVM_REG_PPC_ONLINE (KVM_REG_PPC | KVM_REG_SIZE_U32 | 0xbf)
#define KVM_REG_PPC_PTCR (KVM_REG_PPC | KVM_REG_SIZE_U64 | 0xc0)

+/* POWER10 registers. */
+#define KVM_REG_PPC_DAWR1 (KVM_REG_PPC | KVM_REG_SIZE_U64 | 0xc1)
+#define KVM_REG_PPC_DAWRX1 (KVM_REG_PPC | KVM_REG_SIZE_U64 | 0xc2)
+
/* Transactional Memory checkpointed state:
* This is all GPRs, all VSX regs and a subset of SPRs
*/
--
2.26.2


2020-09-02 02:25:28

by Paul Mackerras

[permalink] [raw]
Subject: Re: [PATCH 2/7] powerpc/watchpoint/kvm: Add infrastructure to support 2nd DAWR

On Thu, Jul 23, 2020 at 03:50:53PM +0530, Ravi Bangoria wrote:
> kvm code assumes single DAWR everywhere. Add code to support 2nd DAWR.
> DAWR is a hypervisor resource and thus H_SET_MODE hcall is used to set/
> unset it. Introduce new case H_SET_MODE_RESOURCE_SET_DAWR1 for 2nd DAWR.

Is this the same interface as will be defined in PAPR and available
under PowerVM, or is it a new/different interface for KVM?

> Also, kvm will support 2nd DAWR only if CPU_FTR_DAWR1 is set.

In general QEMU wants to be able to control all aspects of the virtual
machine presented to the guest, meaning that just because a host has a
particular hardware capability does not mean we should automatically
present that capability to the guest.

In this case, QEMU will want a way to control whether the guest sees
the availability of the second DAWR/X registers or not, i.e. whether a
H_SET_MODE to set DAWR[X]1 will succeed or fail.

Paul.

2020-09-02 05:10:35

by Ravi Bangoria

[permalink] [raw]
Subject: Re: [PATCH 2/7] powerpc/watchpoint/kvm: Add infrastructure to support 2nd DAWR

Hi Paul,

On 9/2/20 7:31 AM, Paul Mackerras wrote:
> On Thu, Jul 23, 2020 at 03:50:53PM +0530, Ravi Bangoria wrote:
>> kvm code assumes single DAWR everywhere. Add code to support 2nd DAWR.
>> DAWR is a hypervisor resource and thus H_SET_MODE hcall is used to set/
>> unset it. Introduce new case H_SET_MODE_RESOURCE_SET_DAWR1 for 2nd DAWR.
>
> Is this the same interface as will be defined in PAPR and available
> under PowerVM, or is it a new/different interface for KVM?

Yes, kvm hcall interface for 2nd DAWR is same as PowerVM, as defined in PAPR.

>
>> Also, kvm will support 2nd DAWR only if CPU_FTR_DAWR1 is set.
>
> In general QEMU wants to be able to control all aspects of the virtual
> machine presented to the guest, meaning that just because a host has a
> particular hardware capability does not mean we should automatically
> present that capability to the guest.
>
> In this case, QEMU will want a way to control whether the guest sees
> the availability of the second DAWR/X registers or not, i.e. whether a
> H_SET_MODE to set DAWR[X]1 will succeed or fail.

Patch #3 adds new kvm capability KVM_CAP_PPC_DAWR1 that can be checked
by Qemu. Also, as suggested by David in Qemu patch[1], I'm planning to
add new machine capability in Qemu:

-machine cap-dawr1=ON/OFF

cap-dawr1 will be default ON when PPC_FEATURE2_ARCH_3_10 is set and OFF
otherwise.

Is this correct approach?

[1]: https://lore.kernel.org/kvm/[email protected]

Thanks,
Ravi

2020-09-02 05:16:18

by Ravi Bangoria

[permalink] [raw]
Subject: Re: [PATCH 2/7] powerpc/watchpoint/kvm: Add infrastructure to support 2nd DAWR

Hi Paul,

> diff --git a/arch/powerpc/include/asm/hvcall.h b/arch/powerpc/include/asm/hvcall.h
> index 33793444144c..03f401d7be41 100644
> --- a/arch/powerpc/include/asm/hvcall.h
> +++ b/arch/powerpc/include/asm/hvcall.h
> @@ -538,6 +538,8 @@ struct hv_guest_state {
> s64 tb_offset;
> u64 dawr0;
> u64 dawrx0;
> + u64 dawr1;
> + u64 dawrx1;
> u64 ciabr;
> u64 hdec_expiry;
> u64 purr;

After this struct, there is a macro HV_GUEST_STATE_VERSION, I guess that
also needs to be incremented because I'm adding new members in the struct?

Thanks,
Ravi