| Message ID | 20240405120108.11844-3-sebott@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: arm64: emulation for CTR_EL0 | expand |
On Fri, 05 Apr 2024 13:01:06 +0100, Sebastian Ott <sebott@redhat.com> wrote: > > In preparation for CTR_EL0 emulation maintain a per VM for this > register and use it where appropriate. > > Signed-off-by: Sebastian Ott <sebott@redhat.com> > --- > arch/arm64/include/asm/kvm_host.h | 1 + > arch/arm64/kvm/sys_regs.c | 22 +++++++++++++++------- > 2 files changed, 16 insertions(+), 7 deletions(-) > > diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h > index 9e8a496fb284..481216febb46 100644 > --- a/arch/arm64/include/asm/kvm_host.h > +++ b/arch/arm64/include/asm/kvm_host.h > @@ -318,6 +318,7 @@ struct kvm_arch { > > /* PMCR_EL0.N value for the guest */ > u8 pmcr_n; > + u64 ctr_el0; > > /* Iterator for idreg debugfs */ > u8 idreg_debugfs_iter; Please consider the alignment of the fields. This leaves a 7 byte hole that could be avoided (yes, I'm on a mission to reduce the size of the various structures, because they are absolute pigs). > diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c > index 131f5b0ca2b9..4d29b1a0842d 100644 > --- a/arch/arm64/kvm/sys_regs.c > +++ b/arch/arm64/kvm/sys_regs.c > @@ -215,13 +215,21 @@ void vcpu_write_sys_reg(struct kvm_vcpu *vcpu, u64 val, int reg) > /* CSSELR values; used to index KVM_REG_ARM_DEMUX_ID_CCSIDR */ > #define CSSELR_MAX 14 > > +static u64 kvm_get_ctr_el0(struct kvm *kvm) > +{ > + if (kvm->arch.ctr_el0) > + return kvm->arch.ctr_el0; Is this relying on some bits not being 0? > + > + return read_sanitised_ftr_reg(SYS_CTR_EL0); Why isn't the shadow value always populated? > +} > + > /* > * Returns the minimum line size for the selected cache, expressed as > * Log2(bytes). > */ > -static u8 get_min_cache_line_size(bool icache) > +static u8 get_min_cache_line_size(struct kvm *kvm, bool icache) > { > - u64 ctr = read_sanitised_ftr_reg(SYS_CTR_EL0); > + u64 ctr = kvm_get_ctr_el0(kvm); > u8 field; > > if (icache) > @@ -248,7 +256,7 @@ static u32 get_ccsidr(struct kvm_vcpu *vcpu, u32 csselr) > if (vcpu->arch.ccsidr) > return vcpu->arch.ccsidr[csselr]; > > - line_size = get_min_cache_line_size(csselr & CSSELR_EL1_InD); > + line_size = get_min_cache_line_size(vcpu->kvm, csselr & CSSELR_EL1_InD); > > /* > * Fabricate a CCSIDR value as the overriding value does not exist. > @@ -283,7 +291,7 @@ static int set_ccsidr(struct kvm_vcpu *vcpu, u32 csselr, u32 val) > u32 i; > > if ((val & CCSIDR_EL1_RES0) || > - line_size < get_min_cache_line_size(csselr & CSSELR_EL1_InD)) > + line_size < get_min_cache_line_size(vcpu->kvm, csselr & CSSELR_EL1_InD)) > return -EINVAL; > > if (!ccsidr) { > @@ -1862,7 +1870,7 @@ static bool access_ctr(struct kvm_vcpu *vcpu, struct sys_reg_params *p, > if (p->is_write) > return write_to_read_only(vcpu, p, r); > > - p->regval = read_sanitised_ftr_reg(SYS_CTR_EL0); > + p->regval = kvm_get_ctr_el0(vcpu->kvm); > return true; > } > > @@ -1882,7 +1890,7 @@ static bool access_clidr(struct kvm_vcpu *vcpu, struct sys_reg_params *p, > */ > static u64 reset_clidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r) > { > - u64 ctr_el0 = read_sanitised_ftr_reg(SYS_CTR_EL0); > + u64 ctr_el0 = kvm_get_ctr_el0(vcpu->kvm); > u64 clidr; > u8 loc; > > @@ -1935,7 +1943,7 @@ static u64 reset_clidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r) > static int set_clidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd, > u64 val) > { > - u64 ctr_el0 = read_sanitised_ftr_reg(SYS_CTR_EL0); > + u64 ctr_el0 = kvm_get_ctr_el0(vcpu->kvm); > u64 idc = !CLIDR_LOC(val) || (!CLIDR_LOUIS(val) && !CLIDR_LOUU(val)); > > if ((val & CLIDR_EL1_RES0) || (!(ctr_el0 & CTR_EL0_IDC) && idc)) Thanks, M.
On Sat, 13 Apr 2024, Marc Zyngier wrote: > On Fri, 05 Apr 2024 13:01:06 +0100, > Sebastian Ott <sebott@redhat.com> wrote: >> >> In preparation for CTR_EL0 emulation maintain a per VM for this >> register and use it where appropriate. >> >> Signed-off-by: Sebastian Ott <sebott@redhat.com> >> --- >> arch/arm64/include/asm/kvm_host.h | 1 + >> arch/arm64/kvm/sys_regs.c | 22 +++++++++++++++------- >> 2 files changed, 16 insertions(+), 7 deletions(-) >> >> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h >> index 9e8a496fb284..481216febb46 100644 >> --- a/arch/arm64/include/asm/kvm_host.h >> +++ b/arch/arm64/include/asm/kvm_host.h >> @@ -318,6 +318,7 @@ struct kvm_arch { >> >> /* PMCR_EL0.N value for the guest */ >> u8 pmcr_n; >> + u64 ctr_el0; >> >> /* Iterator for idreg debugfs */ >> u8 idreg_debugfs_iter; > > Please consider the alignment of the fields. This leaves a 7 byte hole > that could be avoided (yes, I'm on a mission to reduce the size of the > various structures, because they are absolute pigs). OK. >> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c >> index 131f5b0ca2b9..4d29b1a0842d 100644 >> --- a/arch/arm64/kvm/sys_regs.c >> +++ b/arch/arm64/kvm/sys_regs.c >> @@ -215,13 +215,21 @@ void vcpu_write_sys_reg(struct kvm_vcpu *vcpu, u64 val, int reg) >> /* CSSELR values; used to index KVM_REG_ARM_DEMUX_ID_CCSIDR */ >> #define CSSELR_MAX 14 >> >> +static u64 kvm_get_ctr_el0(struct kvm *kvm) >> +{ >> + if (kvm->arch.ctr_el0) >> + return kvm->arch.ctr_el0; > > Is this relying on some bits not being 0? > >> + >> + return read_sanitised_ftr_reg(SYS_CTR_EL0); > > Why isn't the shadow value always populated? The idea was for kvm->arch.ctr_el0 being non zero only if userspace set it up to differ from the host value. So it can be used to decide if we need to set up a trap for the reg access (without comparing it to the host value again). Thanks, Sebastian
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 9e8a496fb284..481216febb46 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -318,6 +318,7 @@ struct kvm_arch { /* PMCR_EL0.N value for the guest */ u8 pmcr_n; + u64 ctr_el0; /* Iterator for idreg debugfs */ u8 idreg_debugfs_iter; diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 131f5b0ca2b9..4d29b1a0842d 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -215,13 +215,21 @@ void vcpu_write_sys_reg(struct kvm_vcpu *vcpu, u64 val, int reg) /* CSSELR values; used to index KVM_REG_ARM_DEMUX_ID_CCSIDR */ #define CSSELR_MAX 14 +static u64 kvm_get_ctr_el0(struct kvm *kvm) +{ + if (kvm->arch.ctr_el0) + return kvm->arch.ctr_el0; + + return read_sanitised_ftr_reg(SYS_CTR_EL0); +} + /* * Returns the minimum line size for the selected cache, expressed as * Log2(bytes). */ -static u8 get_min_cache_line_size(bool icache) +static u8 get_min_cache_line_size(struct kvm *kvm, bool icache) { - u64 ctr = read_sanitised_ftr_reg(SYS_CTR_EL0); + u64 ctr = kvm_get_ctr_el0(kvm); u8 field; if (icache) @@ -248,7 +256,7 @@ static u32 get_ccsidr(struct kvm_vcpu *vcpu, u32 csselr) if (vcpu->arch.ccsidr) return vcpu->arch.ccsidr[csselr]; - line_size = get_min_cache_line_size(csselr & CSSELR_EL1_InD); + line_size = get_min_cache_line_size(vcpu->kvm, csselr & CSSELR_EL1_InD); /* * Fabricate a CCSIDR value as the overriding value does not exist. @@ -283,7 +291,7 @@ static int set_ccsidr(struct kvm_vcpu *vcpu, u32 csselr, u32 val) u32 i; if ((val & CCSIDR_EL1_RES0) || - line_size < get_min_cache_line_size(csselr & CSSELR_EL1_InD)) + line_size < get_min_cache_line_size(vcpu->kvm, csselr & CSSELR_EL1_InD)) return -EINVAL; if (!ccsidr) { @@ -1862,7 +1870,7 @@ static bool access_ctr(struct kvm_vcpu *vcpu, struct sys_reg_params *p, if (p->is_write) return write_to_read_only(vcpu, p, r); - p->regval = read_sanitised_ftr_reg(SYS_CTR_EL0); + p->regval = kvm_get_ctr_el0(vcpu->kvm); return true; } @@ -1882,7 +1890,7 @@ static bool access_clidr(struct kvm_vcpu *vcpu, struct sys_reg_params *p, */ static u64 reset_clidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r) { - u64 ctr_el0 = read_sanitised_ftr_reg(SYS_CTR_EL0); + u64 ctr_el0 = kvm_get_ctr_el0(vcpu->kvm); u64 clidr; u8 loc; @@ -1935,7 +1943,7 @@ static u64 reset_clidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r) static int set_clidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd, u64 val) { - u64 ctr_el0 = read_sanitised_ftr_reg(SYS_CTR_EL0); + u64 ctr_el0 = kvm_get_ctr_el0(vcpu->kvm); u64 idc = !CLIDR_LOC(val) || (!CLIDR_LOUIS(val) && !CLIDR_LOUU(val)); if ((val & CLIDR_EL1_RES0) || (!(ctr_el0 & CTR_EL0_IDC) && idc))
In preparation for CTR_EL0 emulation maintain a per VM for this register and use it where appropriate. Signed-off-by: Sebastian Ott <sebott@redhat.com> --- arch/arm64/include/asm/kvm_host.h | 1 + arch/arm64/kvm/sys_regs.c | 22 +++++++++++++++------- 2 files changed, 16 insertions(+), 7 deletions(-)