| Message ID | 5400AEBA.2080405@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 2014-08-29 18:47, Paolo Bonzini wrote: > Il 19/08/2014 11:04, Wanpeng Li ha scritto: >> Section 11.11.2.3 of the SDM mentions "All other bits in the IA32_MTRR_PHYSBASEn >> and IA32_MTRR_PHYSMASKn registers are reserved; the processor generates a >> general-protection exception(#GP) if software attempts to write to them". This >> patch do it in kvm. >> >> Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com> > > This breaks if the guest maxphyaddr is higher than the host's (which > sometimes happens depending on your hardware and how QEMU is > configured). > > You need to use cpuid_maxphyaddr, like this > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index a375dfc42f6a..916e89515210 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -1726,7 +1726,7 @@ static bool valid_mtrr_type(unsigned t) > static bool mtrr_valid(struct kvm_vcpu *vcpu, u32 msr, u64 data) > { > int i; > - u64 mask = 0; > + u64 mask; > > if (!msr_mtrr_valid(msr)) > return false; > @@ -1750,8 +1750,7 @@ static bool mtrr_valid(struct kvm_vcpu *vcpu, u32 msr, u64 data) > /* variable MTRRs */ > WARN_ON(!(msr >= 0x200 && msr < 0x200 + 2 * KVM_NR_VAR_MTRR)); > > - for (i = 63; i > boot_cpu_data.x86_phys_bits; i--) > - mask |= (1ULL << i); > + mask = (~0ULL) << cpuid_maxphyaddr(vcpu); > if ((msr & 1) == 0) { > /* MTRR base */ > if (!valid_mtrr_type(data & 0xff)) > > > Jan, can you see if this patch fixes the SeaBIOS triple fault you reported? Yep, it does. Jan
On Fri, Aug 29, 2014 at 06:47:54PM +0200, Paolo Bonzini wrote: >Il 19/08/2014 11:04, Wanpeng Li ha scritto: >> Section 11.11.2.3 of the SDM mentions "All other bits in the IA32_MTRR_PHYSBASEn >> and IA32_MTRR_PHYSMASKn registers are reserved; the processor generates a >> general-protection exception(#GP) if software attempts to write to them". This >> patch do it in kvm. >> >> Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com> > >This breaks if the guest maxphyaddr is higher than the host's (which >sometimes happens depending on your hardware and how QEMU is >configured). > >You need to use cpuid_maxphyaddr, like this > >diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c >index a375dfc42f6a..916e89515210 100644 >--- a/arch/x86/kvm/x86.c >+++ b/arch/x86/kvm/x86.c >@@ -1726,7 +1726,7 @@ static bool valid_mtrr_type(unsigned t) > static bool mtrr_valid(struct kvm_vcpu *vcpu, u32 msr, u64 data) > { > int i; >- u64 mask = 0; >+ u64 mask; > > if (!msr_mtrr_valid(msr)) > return false; >@@ -1750,8 +1750,7 @@ static bool mtrr_valid(struct kvm_vcpu *vcpu, u32 msr, u64 data) > /* variable MTRRs */ > WARN_ON(!(msr >= 0x200 && msr < 0x200 + 2 * KVM_NR_VAR_MTRR)); > >- for (i = 63; i > boot_cpu_data.x86_phys_bits; i--) >- mask |= (1ULL << i); >+ mask = (~0ULL) << cpuid_maxphyaddr(vcpu); > if ((msr & 1) == 0) { > /* MTRR base */ > if (!valid_mtrr_type(data & 0xff)) > > Got it, thanks Paolo and Jan. Regards, Wanpeng Li >Jan, can you see if this patch fixes the SeaBIOS triple fault you reported? > >Paolo > >> --- >> arch/x86/kvm/x86.c | 18 +++++++++++++++--- >> 1 file changed, 15 insertions(+), 3 deletions(-) >> >> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c >> index fb3ea7a..b85da5f 100644 >> --- a/arch/x86/kvm/x86.c >> +++ b/arch/x86/kvm/x86.c >> @@ -1726,6 +1726,7 @@ static bool valid_mtrr_type(unsigned t) >> static bool mtrr_valid(struct kvm_vcpu *vcpu, u32 msr, u64 data) >> { >> int i; >> + u64 mask = 0; >> >> if (!msr_mtrr_valid(msr)) >> return false; >> @@ -1749,10 +1750,21 @@ static bool mtrr_valid(struct kvm_vcpu *vcpu, u32 msr, u64 data) >> /* variable MTRRs */ >> WARN_ON(!(msr >= 0x200 && msr < 0x200 + 2 * KVM_NR_VAR_MTRR)); >> >> - if ((msr & 1) == 0) >> + for (i = 63; i > boot_cpu_data.x86_phys_bits; i--) >> + mask |= (1ULL << i); >> + if ((msr & 1) == 0) { >> /* MTRR base */ >> - return valid_mtrr_type(data & 0xff); >> - /* MTRR mask */ >> + if (!valid_mtrr_type(data & 0xff)) >> + return false; >> + mask |= 0xf00; >> + } else >> + /* MTRR mask */ >> + mask |= 0x7ff; >> + if (data & mask) { >> + kvm_inject_gp(vcpu, 0); >> + return false; >> + } >> + >> return true; >> } >> >> -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index a375dfc42f6a..916e89515210 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1726,7 +1726,7 @@ static bool valid_mtrr_type(unsigned t) static bool mtrr_valid(struct kvm_vcpu *vcpu, u32 msr, u64 data) { int i; - u64 mask = 0; + u64 mask; if (!msr_mtrr_valid(msr)) return false; @@ -1750,8 +1750,7 @@ static bool mtrr_valid(struct kvm_vcpu *vcpu, u32 msr, u64 data) /* variable MTRRs */ WARN_ON(!(msr >= 0x200 && msr < 0x200 + 2 * KVM_NR_VAR_MTRR)); - for (i = 63; i > boot_cpu_data.x86_phys_bits; i--) - mask |= (1ULL << i); + mask = (~0ULL) << cpuid_maxphyaddr(vcpu); if ((msr & 1) == 0) { /* MTRR base */ if (!valid_mtrr_type(data & 0xff))