When KVM injects an exception into a guest, it generates the PSTATE
value from scratch, configuring PSTATE.{M[4:0],DAIF}, and setting all
other bits to zero.
This isn't correct, as the architecture specifies that some PSTATE bits
are (conditionally) cleared or set upon an exception, and others are
unchanged from the original context.
This patch adds logic to match the architectural behaviour. To make this
simple to follow/audit/extend, documentation references are provided,
and bits are configured in order of their layout in SPSR_EL2. This
layout can be seen in the diagram on ARM DDI 0487E.a page C5-429.
Signed-off-by: Mark Rutland <mark.rutland(a)arm.com>
Cc: Alexandru Elisei <alexandru.elisei(a)arm.com>
Cc: Drew Jones <drjones(a)redhat.com>
Cc: James Morse <james.morse(a)arm.com>
Cc: Julien Thierry <julien.thierry.kdev(a)gmail.com>
Cc: Marc Zyngier <maz(a)kernel.org>
Cc: Peter Maydell <peter.maydell(a)linaro.org>
Cc: Suzuki K Poulose <suzuki.poulose(a)arm.com>
Cc: Will Deacon <will(a)kernel.org>
Cc: stable(a)vger.kernel.org
---
arch/arm64/include/uapi/asm/ptrace.h | 1 +
arch/arm64/kvm/inject_fault.c | 69 +++++++++++++++++++++++++++++++++---
2 files changed, 65 insertions(+), 5 deletions(-)
diff --git a/arch/arm64/include/uapi/asm/ptrace.h b/arch/arm64/include/uapi/asm/ptrace.h
index 7ed9294e2004..d1bb5b69f1ce 100644
--- a/arch/arm64/include/uapi/asm/ptrace.h
+++ b/arch/arm64/include/uapi/asm/ptrace.h
@@ -49,6 +49,7 @@
#define PSR_SSBS_BIT 0x00001000
#define PSR_PAN_BIT 0x00400000
#define PSR_UAO_BIT 0x00800000
+#define PSR_DIT_BIT 0x01000000
#define PSR_V_BIT 0x10000000
#define PSR_C_BIT 0x20000000
#define PSR_Z_BIT 0x40000000
diff --git a/arch/arm64/kvm/inject_fault.c b/arch/arm64/kvm/inject_fault.c
index a9d25a305af5..270d91c05246 100644
--- a/arch/arm64/kvm/inject_fault.c
+++ b/arch/arm64/kvm/inject_fault.c
@@ -14,9 +14,6 @@
#include <asm/kvm_emulate.h>
#include <asm/esr.h>
-#define PSTATE_FAULT_BITS_64 (PSR_MODE_EL1h | PSR_A_BIT | PSR_F_BIT | \
- PSR_I_BIT | PSR_D_BIT)
-
#define CURRENT_EL_SP_EL0_VECTOR 0x0
#define CURRENT_EL_SP_ELx_VECTOR 0x200
#define LOWER_EL_AArch64_VECTOR 0x400
@@ -50,6 +47,68 @@ static u64 get_except_vector(struct kvm_vcpu *vcpu, enum exception_type type)
return vcpu_read_sys_reg(vcpu, VBAR_EL1) + exc_offset + type;
}
+/*
+ * When an exception is taken, most PSTATE fields are left unchanged in the
+ * handler. However, some are explicitly overridden (e.g. M[4:0]). Luckily all
+ * of the inherited bits have the same position in the AArch64/AArch32 SPSR_ELx
+ * layouts, so we don't need to shuffle these for exceptions from AArch32 EL0.
+ *
+ * For the SPSR_ELx layout for AArch64, see ARM DDI 0487E.a page C5-429.
+ * For the SPSR_ELx layout for AArch32, see ARM DDI 0487E.a page C5-426.
+ *
+ * Here we manipulate the fields in order of the AArch64 SPSR_ELx layout, from
+ * MSB to LSB.
+ */
+static unsigned long get_except64_pstate(struct kvm_vcpu *vcpu)
+{
+ unsigned long sctlr = vcpu_read_sys_reg(vcpu, SCTLR_EL1);
+ unsigned long old, new;
+
+ old = *vcpu_cpsr(vcpu);
+ new = 0;
+
+ new |= (old & PSR_N_BIT);
+ new |= (old & PSR_Z_BIT);
+ new |= (old & PSR_C_BIT);
+ new |= (old & PSR_V_BIT);
+
+ // TODO: TCO (if/when ARMv8.5-MemTag is exposed to guests)
+
+ new |= (old & PSR_DIT_BIT);
+
+ // PSTATE.UAO is set to zero upon any exception to AArch64
+ // See ARM DDI 0487E.a, page D5-2579.
+
+ // PSTATE.PAN is unchanged unless overridden by SCTLR_ELx.SPAN
+ // See ARM DDI 0487E.a, page D5-2578.
+ new |= (old & PSR_PAN_BIT);
+ if (sctlr & SCTLR_EL1_SPAN)
+ new |= PSR_PAN_BIT;
+
+ // PSTATE.SS is set to zero upon any exception to AArch64
+ // See ARM DDI 0487E.a, page D2-2452.
+
+ // PSTATE.IL is set to zero upon any exception to AArch64
+ // See ARM DDI 0487E.a, page D1-2306.
+
+ // PSTATE.SSBS is set to SCTLR_ELx.DSSBS upon any exception to AArch64
+ // See ARM DDI 0487E.a, page D13-3258
+ if (sctlr & SCTLR_ELx_DSSBS)
+ new |= PSR_SSBS_BIT;
+
+ // PSTATE.BTYPE is set to zero upon any exception to AArch64
+ // See ARM DDI 0487E.a, pages D1-2293 to D1-2294.
+
+ new |= PSR_D_BIT;
+ new |= PSR_A_BIT;
+ new |= PSR_I_BIT;
+ new |= PSR_F_BIT;
+
+ new |= PSR_MODE_EL1h;
+
+ return new;
+}
+
static void inject_abt64(struct kvm_vcpu *vcpu, bool is_iabt, unsigned long addr)
{
unsigned long cpsr = *vcpu_cpsr(vcpu);
@@ -59,7 +118,7 @@ static void inject_abt64(struct kvm_vcpu *vcpu, bool is_iabt, unsigned long addr
vcpu_write_elr_el1(vcpu, *vcpu_pc(vcpu));
*vcpu_pc(vcpu) = get_except_vector(vcpu, except_type_sync);
- *vcpu_cpsr(vcpu) = PSTATE_FAULT_BITS_64;
+ *vcpu_cpsr(vcpu) = get_except64_pstate(vcpu);
vcpu_write_spsr(vcpu, cpsr);
vcpu_write_sys_reg(vcpu, addr, FAR_EL1);
@@ -94,7 +153,7 @@ static void inject_undef64(struct kvm_vcpu *vcpu)
vcpu_write_elr_el1(vcpu, *vcpu_pc(vcpu));
*vcpu_pc(vcpu) = get_except_vector(vcpu, except_type_sync);
- *vcpu_cpsr(vcpu) = PSTATE_FAULT_BITS_64;
+ *vcpu_cpsr(vcpu) = get_except64_pstate(vcpu);
vcpu_write_spsr(vcpu, cpsr);
/*
--
2.11.0
Use our default values when wrong module-parameters are given, instead of
refusing to load. Refusing to load leaves the fan at the BIOS default
setting, which is "Off". The CPU's thermal throttling should protect the
system from damage, but not-loading is really not the best fallback in this
case.
This commit fixes this by re-setting module-parameter values to their
defaults if they are out of range, instead of failing the probe with
-EINVAL.
Cc: stable(a)vger.kernel.org
Cc: Jason Anderson <jasona.594(a)gmail.com>
Reported-by: Jason Anderson <jasona.594(a)gmail.com>
Fixes: 594ce6db326e ("platform/x86: GPD pocket fan: Use a min-speed of 2 while charging")
Signed-off-by: Hans de Goede <hdegoede(a)redhat.com>
---
drivers/platform/x86/gpd-pocket-fan.c | 24 ++++++++++++++++++------
1 file changed, 18 insertions(+), 6 deletions(-)
diff --git a/drivers/platform/x86/gpd-pocket-fan.c b/drivers/platform/x86/gpd-pocket-fan.c
index be85ed966bf3..1e6a42f2ea8a 100644
--- a/drivers/platform/x86/gpd-pocket-fan.c
+++ b/drivers/platform/x86/gpd-pocket-fan.c
@@ -16,17 +16,26 @@
#define MAX_SPEED 3
-static int temp_limits[3] = { 55000, 60000, 65000 };
+#define TEMP_LIMIT0_DEFAULT 55000
+#define TEMP_LIMIT1_DEFAULT 60000
+#define TEMP_LIMIT2_DEFAULT 65000
+
+#define HYSTERESIS_DEFAULT 3000
+
+#define SPEED_ON_AC_DEFAULT 2
+
+static int temp_limits[3] = {
+ TEMP_LIMIT0_DEFAULT, TEMP_LIMIT1_DEFAULT, TEMP_LIMIT2_DEFAULT };
module_param_array(temp_limits, int, NULL, 0444);
MODULE_PARM_DESC(temp_limits,
"Millicelsius values above which the fan speed increases");
-static int hysteresis = 3000;
+static int hysteresis = HYSTERESIS_DEFAULT;
module_param(hysteresis, int, 0444);
MODULE_PARM_DESC(hysteresis,
"Hysteresis in millicelsius before lowering the fan speed");
-static int speed_on_ac = 2;
+static int speed_on_ac = SPEED_ON_AC_DEFAULT;
module_param(speed_on_ac, int, 0444);
MODULE_PARM_DESC(speed_on_ac,
"minimum fan speed to allow when system is powered by AC");
@@ -120,18 +129,21 @@ static int gpd_pocket_fan_probe(struct platform_device *pdev)
if (temp_limits[i] < 40000 || temp_limits[i] > 70000) {
dev_err(&pdev->dev, "Invalid temp-limit %d (must be between 40000 and 70000)\n",
temp_limits[i]);
- return -EINVAL;
+ temp_limits[0] = TEMP_LIMIT0_DEFAULT;
+ temp_limits[1] = TEMP_LIMIT1_DEFAULT;
+ temp_limits[2] = TEMP_LIMIT2_DEFAULT;
+ break;
}
}
if (hysteresis < 1000 || hysteresis > 10000) {
dev_err(&pdev->dev, "Invalid hysteresis %d (must be between 1000 and 10000)\n",
hysteresis);
- return -EINVAL;
+ hysteresis = HYSTERESIS_DEFAULT;
}
if (speed_on_ac < 0 || speed_on_ac > MAX_SPEED) {
dev_err(&pdev->dev, "Invalid speed_on_ac %d (must be between 0 and 3)\n",
speed_on_ac);
- return -EINVAL;
+ speed_on_ac = SPEED_ON_AC_DEFAULT;
}
fan = devm_kzalloc(&pdev->dev, sizeof(*fan), GFP_KERNEL);
--
2.24.1
When KVM injects an exception into a guest, it generates the CPSR value
from scratch, configuring CPSR.{M,A,I,T,E}, and setting all other
bits to zero.
This isn't correct, as the architecture specifies that some CPSR bits
are (conditionally) cleared or set upon an exception, and others are
unchanged from the original context.
This patch adds logic to match the architectural behaviour. To make this
simple to follow/audit/extend, documentation references are provided,
and bits are configured in order of their layout in SPSR_EL2. This
layout can be seen in the diagram on ARM DDI 0487E.a page C5-426.
Signed-off-by: Mark Rutland <mark.rutland(a)arm.com>
Cc: Alexandru Elisei <alexandru.elisei(a)arm.com>
Cc: Drew Jones <drjones(a)redhat.com>
Cc: James Morse <james.morse(a)arm.com>
Cc: Julien Thierry <julien.thierry.kdev(a)gmail.com>
Cc: Marc Zyngier <maz(a)kernel.org>
Cc: Peter Maydell <peter.maydell(a)linaro.org>
Cc: Suzuki K Poulose <suzuki.poulose(a)arm.com>
Cc: Will Deacon <will(a)kernel.org>
Cc: stable(a)vger.kernel.org
---
arch/arm/include/asm/kvm_emulate.h | 12 ++++
arch/arm64/include/asm/ptrace.h | 1 +
virt/kvm/arm/aarch32.c | 110 +++++++++++++++++++++++++++++++++----
3 files changed, 113 insertions(+), 10 deletions(-)
diff --git a/arch/arm/include/asm/kvm_emulate.h b/arch/arm/include/asm/kvm_emulate.h
index 40002416efec..dee2567661ed 100644
--- a/arch/arm/include/asm/kvm_emulate.h
+++ b/arch/arm/include/asm/kvm_emulate.h
@@ -14,13 +14,25 @@
#include <asm/cputype.h>
/* arm64 compatibility macros */
+#define PSR_AA32_MODE_FIQ FIQ_MODE
+#define PSR_AA32_MODE_SVC SVC_MODE
#define PSR_AA32_MODE_ABT ABT_MODE
#define PSR_AA32_MODE_UND UND_MODE
#define PSR_AA32_T_BIT PSR_T_BIT
+#define PSR_AA32_F_BIT PSR_F_BIT
#define PSR_AA32_I_BIT PSR_I_BIT
#define PSR_AA32_A_BIT PSR_A_BIT
#define PSR_AA32_E_BIT PSR_E_BIT
#define PSR_AA32_IT_MASK PSR_IT_MASK
+#define PSR_AA32_GE_MASK 0x000f0000
+#define PSR_AA32_PAN_BIT 0x00400000
+#define PSR_AA32_SSBS_BIT 0x00800000
+#define PSR_AA32_DIT_BIT 0x01000000
+#define PSR_AA32_Q_BIT PSR_Q_BIT
+#define PSR_AA32_V_BIT PSR_V_BIT
+#define PSR_AA32_C_BIT PSR_C_BIT
+#define PSR_AA32_Z_BIT PSR_Z_BIT
+#define PSR_AA32_N_BIT PSR_N_BIT
unsigned long *vcpu_reg(struct kvm_vcpu *vcpu, u8 reg_num);
diff --git a/arch/arm64/include/asm/ptrace.h b/arch/arm64/include/asm/ptrace.h
index fbebb411ae20..bf57308fcd63 100644
--- a/arch/arm64/include/asm/ptrace.h
+++ b/arch/arm64/include/asm/ptrace.h
@@ -62,6 +62,7 @@
#define PSR_AA32_I_BIT 0x00000080
#define PSR_AA32_A_BIT 0x00000100
#define PSR_AA32_E_BIT 0x00000200
+#define PSR_AA32_PAN_BIT 0x00400000
#define PSR_AA32_SSBS_BIT 0x00800000
#define PSR_AA32_DIT_BIT 0x01000000
#define PSR_AA32_Q_BIT 0x08000000
diff --git a/virt/kvm/arm/aarch32.c b/virt/kvm/arm/aarch32.c
index c4c57ba99e90..17bcde5c2451 100644
--- a/virt/kvm/arm/aarch32.c
+++ b/virt/kvm/arm/aarch32.c
@@ -10,6 +10,7 @@
* Author: Christoffer Dall <c.dall(a)virtualopensystems.com>
*/
+#include <linux/bits.h>
#include <linux/kvm_host.h>
#include <asm/kvm_emulate.h>
#include <asm/kvm_hyp.h>
@@ -28,22 +29,111 @@ static const u8 return_offsets[8][2] = {
[7] = { 4, 4 }, /* FIQ, unused */
};
+/*
+ * When an exception is taken, most CPSR fields are left unchanged in the
+ * handler. However, some are explicitly overridden (e.g. M[4:0]).
+ *
+ * The SPSR/SPSR_ELx layouts differ, and the below is intended to work with
+ * either format. Note: SPSR.J bit doesn't exist in SPSR_ELx, but this bit was
+ * obsoleted by the ARMv7 virtualization extensions and is RES0.
+ *
+ * For the SPSR layout seen from AArch32, see:
+ * - ARM DDI 0406C.d, page B1-1148
+ * - ARM DDI 0487E.a, page G8-6264
+ *
+ * For the SPSR_ELx layout for AArch32 seen from AArch64, see:
+ * - ARM DDI 0487E.a, page C5-426
+ *
+ * Here we manipulate the fields in order of the AArch32 SPSR_ELx layout, from
+ * MSB to LSB.
+ */
+static unsigned long get_except32_cpsr(struct kvm_vcpu *vcpu, u32 mode)
+{
+ u32 sctlr = vcpu_cp15(vcpu, c1_SCTLR);
+ unsigned long old, new;
+
+ old = *vcpu_cpsr(vcpu);
+ new = 0;
+
+ new |= (old & PSR_AA32_N_BIT);
+ new |= (old & PSR_AA32_Z_BIT);
+ new |= (old & PSR_AA32_C_BIT);
+ new |= (old & PSR_AA32_V_BIT);
+ new |= (old & PSR_AA32_Q_BIT);
+
+ // CPSR.IT[7:0] are set to zero upon any exception
+ // See ARM DDI 0487E.a, section G1.12.3
+ // See ARM DDI 0406C.d, section B1.8.3
+
+ new |= (old & PSR_AA32_DIT_BIT);
+
+ // CPSR.SSBS is set to SCTLR.DSSBS upon any exception
+ // See ARM DDI 0487E.a, page G8-6244
+ if (sctlr & BIT(31))
+ new |= PSR_AA32_SSBS_BIT;
+
+ // CPSR.PAN is unchanged unless overridden by SCTLR.SPAN
+ // See ARM DDI 0487E.a, page G8-6246
+ new |= (old & PSR_AA32_PAN_BIT);
+ if (sctlr & BIT(23))
+ new |= PSR_AA32_PAN_BIT;
+
+ // SS does not exist in AArch32, so ignore
+
+ // CPSR.IL is set to zero upon any exception
+ // See ARM DDI 0487E.a, page G1-5527
+
+ new |= (old & PSR_AA32_GE_MASK);
+
+ // CPSR.IT[7:0] are set to zero upon any exception
+ // See prior comment above
+
+ // CPSR.E is set to SCTLR.EE upon any exception
+ // See ARM DDI 0487E.a, page G8-6245
+ // See ARM DDI 0406C.d, page B4-1701
+ if (sctlr & BIT(25))
+ new |= PSR_AA32_E_BIT;
+
+ // CPSR.A is unchanged upon an exception to Undefined, Supervisor
+ // CPSR.A is set upon an exception to other modes
+ // See ARM DDI 0487E.a, pages G1-5515 to G1-5516
+ // See ARM DDI 0406C.d, page B1-1182
+ new |= (old & PSR_AA32_A_BIT);
+ if (mode != PSR_AA32_MODE_UND && mode != PSR_AA32_MODE_SVC)
+ new |= PSR_AA32_A_BIT;
+
+ // CPSR.I is set upon any exception
+ // See ARM DDI 0487E.a, pages G1-5515 to G1-5516
+ // See ARM DDI 0406C.d, page B1-1182
+ new |= PSR_AA32_I_BIT;
+
+ // CPSR.F is set upon an exception to FIQ
+ // CPSR.F is unchanged upon an exception to other modes
+ // See ARM DDI 0487E.a, pages G1-5515 to G1-5516
+ // See ARM DDI 0406C.d, page B1-1182
+ new |= (old & PSR_AA32_F_BIT);
+ if (mode == PSR_AA32_MODE_FIQ)
+ new |= PSR_AA32_F_BIT;
+
+ // CPSR.T is set to SCTLR.TE upon any exception
+ // See ARM DDI 0487E.a, page G8-5514
+ // See ARM DDI 0406C.d, page B1-1181
+ if (sctlr & BIT(30))
+ new |= PSR_AA32_T_BIT;
+
+ new |= mode;
+
+ return new;
+}
+
static void prepare_fault32(struct kvm_vcpu *vcpu, u32 mode, u32 vect_offset)
{
- unsigned long cpsr;
unsigned long new_spsr_value = *vcpu_cpsr(vcpu);
bool is_thumb = (new_spsr_value & PSR_AA32_T_BIT);
u32 return_offset = return_offsets[vect_offset >> 2][is_thumb];
u32 sctlr = vcpu_cp15(vcpu, c1_SCTLR);
- cpsr = mode | PSR_AA32_I_BIT;
-
- if (sctlr & (1 << 30))
- cpsr |= PSR_AA32_T_BIT;
- if (sctlr & (1 << 25))
- cpsr |= PSR_AA32_E_BIT;
-
- *vcpu_cpsr(vcpu) = cpsr;
+ *vcpu_cpsr(vcpu) = get_except32_cpsr(vcpu, mode);
/* Note: These now point to the banked copies */
vcpu_write_spsr(vcpu, new_spsr_value);
@@ -84,7 +174,7 @@ static void inject_abt32(struct kvm_vcpu *vcpu, bool is_pabt,
fsr = &vcpu_cp15(vcpu, c5_DFSR);
}
- prepare_fault32(vcpu, PSR_AA32_MODE_ABT | PSR_AA32_A_BIT, vect_offset);
+ prepare_fault32(vcpu, PSR_AA32_MODE_ABT, vect_offset);
*far = addr;
--
2.11.0