| Message ID | 1425479753-18349-6-git-send-email-alex.bennee@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, Mar 04, 2015 at 02:35:52PM +0000, Alex Bennée wrote: > From: Christoffer Dall <christoffer.dall@linaro.org> > > The current code was negatively indexing the cpu state array and not > synchronizing banked spsr register state with the current mode's spsr > state, causing occasional failures with migration. > > Some munging is done to take care of the aarch64 mapping and also to > ensure the most current value of the spsr is updated to the banked > registers (relevant for KVM<->TCG migration). > > Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> > Signed-off-by: Alex Bennée <alex.bennee@linaro.org> > > --- > v2 (ajb) > - minor tweaks and clarifications > v3 > - Use the correct bank index function for setting/getting env->spsr > - only deal with spsrs in elevated exception levels > > diff --git a/target-arm/kvm64.c b/target-arm/kvm64.c > index c60e989..45e5c3f 100644 > --- a/target-arm/kvm64.c > +++ b/target-arm/kvm64.c > @@ -140,6 +140,7 @@ int kvm_arch_put_registers(CPUState *cs, int level) > uint64_t val; > int i; > int ret; > + unsigned int el; > > ARMCPU *cpu = ARM_CPU(cs); > CPUARMState *env = &cpu->env; > @@ -206,9 +207,27 @@ int kvm_arch_put_registers(CPUState *cs, int level) > return ret; > } > > + /* Saved Program State Registers > + * > + * Before we restore from the banked_spsr[] array we need to > + * ensure that any modifications to env->spsr are correctly > + * reflected and map aarch64 exception levels if required. > + */ > + el = arm_current_el(env); > + if (el > 0) { > + if (is_a64(env)) { > + g_assert(el == 1); > + /* KVM only maps KVM_SPSR_SVC to KVM_SPSR_EL1 for aarch64 ATM */ not sure about the 'for aarch64' comment; I would say that it's for aarch32 support. Also, you can drop the ATM, since this is user space ABI that we don't change easily. don't you need to do env->banked_spsr[0] = env->spsr first? > + env->banked_spsr[1] = env->banked_spsr[0]; > + } else { > + i = bank_number(env->uncached_cpsr & CPSR_M); > + env->banked_spsr[i] = env->spsr; so here we don't need to worry about banked_spsr[1] = banked_spsr[0] because banked_spsr[0] is meaningless for 32-bit state and we only sync banked_spsr[1] and up to KVM, correct? I think this is what may deserve a comment. > + } > + } > + > for (i = 0; i < KVM_NR_SPSR; i++) { > reg.id = AARCH64_CORE_REG(spsr[i]); > - reg.addr = (uintptr_t) &env->banked_spsr[i - 1]; > + reg.addr = (uintptr_t) &env->banked_spsr[i+1]; > ret = kvm_vcpu_ioctl(cs, KVM_SET_ONE_REG, ®); > if (ret) { > return ret; > @@ -253,6 +272,7 @@ int kvm_arch_get_registers(CPUState *cs) > struct kvm_one_reg reg; > uint64_t val; > uint32_t fpr; > + unsigned int el; > int i; > int ret; > > @@ -325,15 +345,35 @@ int kvm_arch_get_registers(CPUState *cs) > return ret; > } > > + /* Fetch the SPSR registers > + * > + * KVM has an array of state indexed for all the possible aarch32 > + * privilage levels. Although not all are valid at all points privilege > + * there are some transitions possible which can access old state > + * so it is worth keeping them all. > + */ dubious comment overall > for (i = 0; i < KVM_NR_SPSR; i++) { > reg.id = AARCH64_CORE_REG(spsr[i]); > - reg.addr = (uintptr_t) &env->banked_spsr[i - 1]; > + reg.addr = (uintptr_t) &env->banked_spsr[i+1]; > ret = kvm_vcpu_ioctl(cs, KVM_GET_ONE_REG, ®); > if (ret) { > return ret; > } > } > > + el = arm_current_el(env); > + if (el > 0) { > + if (is_a64(env)) { > + g_assert(el == 1); > + /* KVM maps KVM_SPSR_SVC to KVM_SPSR_EL1 for aarch64 */ same as above > + env->banked_spsr[0] = env->banked_spsr[1]; > + i = aarch64_banked_spsr_index(el); > + } else { > + i = bank_number(env->uncached_cpsr & CPSR_M); same potential place for comment as above. > + } > + env->spsr = env->banked_spsr[i]; > + } > + > /* Advanced SIMD and FP registers */ > for (i = 0; i < 32; i++) { > reg.id = AARCH64_SIMD_CORE_REG(fp_regs.vregs[i]); > -- > 2.3.1 >
On Mon, Mar 9, 2015 at 8:26 AM, Christoffer Dall <christoffer.dall@linaro.org> wrote: > On Wed, Mar 04, 2015 at 02:35:52PM +0000, Alex Bennée wrote: >> From: Christoffer Dall <christoffer.dall@linaro.org> >> >> The current code was negatively indexing the cpu state array and not >> synchronizing banked spsr register state with the current mode's spsr >> state, causing occasional failures with migration. >> >> Some munging is done to take care of the aarch64 mapping and also to >> ensure the most current value of the spsr is updated to the banked >> registers (relevant for KVM<->TCG migration). >> >> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> >> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> >> >> --- >> v2 (ajb) >> - minor tweaks and clarifications >> v3 >> - Use the correct bank index function for setting/getting env->spsr >> - only deal with spsrs in elevated exception levels >> >> diff --git a/target-arm/kvm64.c b/target-arm/kvm64.c >> index c60e989..45e5c3f 100644 >> --- a/target-arm/kvm64.c >> +++ b/target-arm/kvm64.c >> @@ -140,6 +140,7 @@ int kvm_arch_put_registers(CPUState *cs, int level) >> uint64_t val; >> int i; >> int ret; >> + unsigned int el; >> >> ARMCPU *cpu = ARM_CPU(cs); >> CPUARMState *env = &cpu->env; >> @@ -206,9 +207,27 @@ int kvm_arch_put_registers(CPUState *cs, int level) >> return ret; >> } >> >> + /* Saved Program State Registers >> + * >> + * Before we restore from the banked_spsr[] array we need to >> + * ensure that any modifications to env->spsr are correctly >> + * reflected and map aarch64 exception levels if required. >> + */ >> + el = arm_current_el(env); >> + if (el > 0) { >> + if (is_a64(env)) { >> + g_assert(el == 1); >> + /* KVM only maps KVM_SPSR_SVC to KVM_SPSR_EL1 for aarch64 ATM */ > > not sure about the 'for aarch64' comment; I would say that it's for > aarch32 support. Also, you can drop the ATM, since this is user space > ABI that we don't change easily. > > > don't you need to do env->banked_spsr[0] = env->spsr first? I agree with Christoffer, env->spsr actually has the most current value so you need to sync up with it before sending it out. > >> + env->banked_spsr[1] = env->banked_spsr[0]; > > >> + } else { >> + i = bank_number(env->uncached_cpsr & CPSR_M); >> + env->banked_spsr[i] = env->spsr; > > so here we don't need to worry about banked_spsr[1] = banked_spsr[0] > because banked_spsr[0] is meaningless for 32-bit state and we only sync > banked_spsr[1] and up to KVM, correct? I think this is what may deserve > a comment. > >> + } >> + } >> + >> for (i = 0; i < KVM_NR_SPSR; i++) { >> reg.id = AARCH64_CORE_REG(spsr[i]); >> - reg.addr = (uintptr_t) &env->banked_spsr[i - 1]; >> + reg.addr = (uintptr_t) &env->banked_spsr[i+1]; >> ret = kvm_vcpu_ioctl(cs, KVM_SET_ONE_REG, ®); >> if (ret) { >> return ret; >> @@ -253,6 +272,7 @@ int kvm_arch_get_registers(CPUState *cs) >> struct kvm_one_reg reg; >> uint64_t val; >> uint32_t fpr; >> + unsigned int el; >> int i; >> int ret; >> >> @@ -325,15 +345,35 @@ int kvm_arch_get_registers(CPUState *cs) >> return ret; >> } >> >> + /* Fetch the SPSR registers >> + * >> + * KVM has an array of state indexed for all the possible aarch32 >> + * privilage levels. Although not all are valid at all points > > privilege > >> + * there are some transitions possible which can access old state >> + * so it is worth keeping them all. >> + */ > > dubious comment overall > >> for (i = 0; i < KVM_NR_SPSR; i++) { >> reg.id = AARCH64_CORE_REG(spsr[i]); >> - reg.addr = (uintptr_t) &env->banked_spsr[i - 1]; >> + reg.addr = (uintptr_t) &env->banked_spsr[i+1]; >> ret = kvm_vcpu_ioctl(cs, KVM_GET_ONE_REG, ®); >> if (ret) { >> return ret; >> } >> } >> >> + el = arm_current_el(env); >> + if (el > 0) { >> + if (is_a64(env)) { >> + g_assert(el == 1); >> + /* KVM maps KVM_SPSR_SVC to KVM_SPSR_EL1 for aarch64 */ > > same as above If Christoffer's comment is referring to updating env->spsr, it occurs below based on 'i'. > >> + env->banked_spsr[0] = env->banked_spsr[1]; >> + i = aarch64_banked_spsr_index(el); >> + } else { >> + i = bank_number(env->uncached_cpsr & CPSR_M); > > same potential place for comment as above. > >> + } >> + env->spsr = env->banked_spsr[i]; >> + } >> + >> /* Advanced SIMD and FP registers */ >> for (i = 0; i < 32; i++) { >> reg.id = AARCH64_SIMD_CORE_REG(fp_regs.vregs[i]); >> -- >> 2.3.1 >> >
diff --git a/target-arm/kvm64.c b/target-arm/kvm64.c index c60e989..45e5c3f 100644 --- a/target-arm/kvm64.c +++ b/target-arm/kvm64.c @@ -140,6 +140,7 @@ int kvm_arch_put_registers(CPUState *cs, int level) uint64_t val; int i; int ret; + unsigned int el; ARMCPU *cpu = ARM_CPU(cs); CPUARMState *env = &cpu->env; @@ -206,9 +207,27 @@ int kvm_arch_put_registers(CPUState *cs, int level) return ret; } + /* Saved Program State Registers + * + * Before we restore from the banked_spsr[] array we need to + * ensure that any modifications to env->spsr are correctly + * reflected and map aarch64 exception levels if required. + */ + el = arm_current_el(env); + if (el > 0) { + if (is_a64(env)) { + g_assert(el == 1); + /* KVM only maps KVM_SPSR_SVC to KVM_SPSR_EL1 for aarch64 ATM */ + env->banked_spsr[1] = env->banked_spsr[0]; + } else { + i = bank_number(env->uncached_cpsr & CPSR_M); + env->banked_spsr[i] = env->spsr; + } + } + for (i = 0; i < KVM_NR_SPSR; i++) { reg.id = AARCH64_CORE_REG(spsr[i]); - reg.addr = (uintptr_t) &env->banked_spsr[i - 1]; + reg.addr = (uintptr_t) &env->banked_spsr[i+1]; ret = kvm_vcpu_ioctl(cs, KVM_SET_ONE_REG, ®); if (ret) { return ret; @@ -253,6 +272,7 @@ int kvm_arch_get_registers(CPUState *cs) struct kvm_one_reg reg; uint64_t val; uint32_t fpr; + unsigned int el; int i; int ret; @@ -325,15 +345,35 @@ int kvm_arch_get_registers(CPUState *cs) return ret; } + /* Fetch the SPSR registers + * + * KVM has an array of state indexed for all the possible aarch32 + * privilage levels. Although not all are valid at all points + * there are some transitions possible which can access old state + * so it is worth keeping them all. + */ for (i = 0; i < KVM_NR_SPSR; i++) { reg.id = AARCH64_CORE_REG(spsr[i]); - reg.addr = (uintptr_t) &env->banked_spsr[i - 1]; + reg.addr = (uintptr_t) &env->banked_spsr[i+1]; ret = kvm_vcpu_ioctl(cs, KVM_GET_ONE_REG, ®); if (ret) { return ret; } } + el = arm_current_el(env); + if (el > 0) { + if (is_a64(env)) { + g_assert(el == 1); + /* KVM maps KVM_SPSR_SVC to KVM_SPSR_EL1 for aarch64 */ + env->banked_spsr[0] = env->banked_spsr[1]; + i = aarch64_banked_spsr_index(el); + } else { + i = bank_number(env->uncached_cpsr & CPSR_M); + } + env->spsr = env->banked_spsr[i]; + } + /* Advanced SIMD and FP registers */ for (i = 0; i < 32; i++) { reg.id = AARCH64_SIMD_CORE_REG(fp_regs.vregs[i]);