| Message ID | 20210208201502.1239867-1-seanjc@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: x86/xen: Use hva_t for holding hypercall page address | expand |
On Mon, 2021-02-08 at 12:15 -0800, Sean Christopherson wrote: > Use hva_t, a.k.a. unsigned long, for the local variable that holds the > hypercall page address. On 32-bit KVM, gcc complains about using a u64 > due to the implicit cast from a 64-bit value to a 32-bit pointer. > > arch/x86/kvm/xen.c: In function ‘kvm_xen_write_hypercall_page’: > arch/x86/kvm/xen.c:300:22: error: cast to pointer from integer of > different size [-Werror=int-to-pointer-cast] > 300 | page = memdup_user((u8 __user *)blob_addr, PAGE_SIZE); Thanks. Acked-by: David Woodhouse <dwmw@amazon.co.uk> > Cc: Joao Martins <joao.m.martins@oracle.com> > Cc: David Woodhouse <dwmw@amazon.co.uk> > Fixes: 23200b7a30de ("KVM: x86/xen: intercept xen hypercalls if enabled") > Signed-off-by: Sean Christopherson <seanjc@google.com> > --- > arch/x86/kvm/xen.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c > index 2cee0376455c..deda1ba8c18a 100644 > --- a/arch/x86/kvm/xen.c > +++ b/arch/x86/kvm/xen.c > @@ -286,8 +286,12 @@ int kvm_xen_write_hypercall_page(struct kvm_vcpu *vcpu, u64 data) > return 1; > } > } else { > - u64 blob_addr = lm ? kvm->arch.xen_hvm_config.blob_addr_64 > - : kvm->arch.xen_hvm_config.blob_addr_32; > + /* > + * Note, truncation is a non-issue as 'lm' is guaranteed to be > + * false for a 32-bit kernel, i.e. when hva_t is only 4 bytes. > + */ > + hva_t blob_addr = lm ? kvm->arch.xen_hvm_config.blob_addr_64 > + : kvm->arch.xen_hvm_config.blob_addr_32; > u8 blob_size = lm ? kvm->arch.xen_hvm_config.blob_size_64 > : kvm->arch.xen_hvm_config.blob_size_32; > u8 *page; > -- > 2.30.0.478.g8a0d178c01-goog > Amazon Development Centre (London) Ltd. Registered in England and Wales with registration number 04543232 with its registered office at 1 Principal Place, Worship Street, London EC2A 2FA, United Kingdom.
On 2/8/21 8:15 PM, Sean Christopherson wrote: > Use hva_t, a.k.a. unsigned long, for the local variable that holds the > hypercall page address. On 32-bit KVM, gcc complains about using a u64 > due to the implicit cast from a 64-bit value to a 32-bit pointer. > > arch/x86/kvm/xen.c: In function ‘kvm_xen_write_hypercall_page’: > arch/x86/kvm/xen.c:300:22: error: cast to pointer from integer of > different size [-Werror=int-to-pointer-cast] > 300 | page = memdup_user((u8 __user *)blob_addr, PAGE_SIZE); > > Cc: Joao Martins <joao.m.martins@oracle.com> > Cc: David Woodhouse <dwmw@amazon.co.uk> > Fixes: 23200b7a30de ("KVM: x86/xen: intercept xen hypercalls if enabled") > Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Joao Martins <joao.m.martins@oracle.com> > --- > arch/x86/kvm/xen.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c > index 2cee0376455c..deda1ba8c18a 100644 > --- a/arch/x86/kvm/xen.c > +++ b/arch/x86/kvm/xen.c > @@ -286,8 +286,12 @@ int kvm_xen_write_hypercall_page(struct kvm_vcpu *vcpu, u64 data) > return 1; > } > } else { > - u64 blob_addr = lm ? kvm->arch.xen_hvm_config.blob_addr_64 > - : kvm->arch.xen_hvm_config.blob_addr_32; > + /* > + * Note, truncation is a non-issue as 'lm' is guaranteed to be > + * false for a 32-bit kernel, i.e. when hva_t is only 4 bytes. > + */ > + hva_t blob_addr = lm ? kvm->arch.xen_hvm_config.blob_addr_64 > + : kvm->arch.xen_hvm_config.blob_addr_32; > u8 blob_size = lm ? kvm->arch.xen_hvm_config.blob_size_64 > : kvm->arch.xen_hvm_config.blob_size_32; > u8 *page; >
On 08/02/21 21:15, Sean Christopherson wrote: > Use hva_t, a.k.a. unsigned long, for the local variable that holds the > hypercall page address. On 32-bit KVM, gcc complains about using a u64 > due to the implicit cast from a 64-bit value to a 32-bit pointer. > > arch/x86/kvm/xen.c: In function ‘kvm_xen_write_hypercall_page’: > arch/x86/kvm/xen.c:300:22: error: cast to pointer from integer of > different size [-Werror=int-to-pointer-cast] > 300 | page = memdup_user((u8 __user *)blob_addr, PAGE_SIZE); > > Cc: Joao Martins <joao.m.martins@oracle.com> > Cc: David Woodhouse <dwmw@amazon.co.uk> > Fixes: 23200b7a30de ("KVM: x86/xen: intercept xen hypercalls if enabled") > Signed-off-by: Sean Christopherson <seanjc@google.com> > --- > arch/x86/kvm/xen.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c > index 2cee0376455c..deda1ba8c18a 100644 > --- a/arch/x86/kvm/xen.c > +++ b/arch/x86/kvm/xen.c > @@ -286,8 +286,12 @@ int kvm_xen_write_hypercall_page(struct kvm_vcpu *vcpu, u64 data) > return 1; > } > } else { > - u64 blob_addr = lm ? kvm->arch.xen_hvm_config.blob_addr_64 > - : kvm->arch.xen_hvm_config.blob_addr_32; > + /* > + * Note, truncation is a non-issue as 'lm' is guaranteed to be > + * false for a 32-bit kernel, i.e. when hva_t is only 4 bytes. > + */ > + hva_t blob_addr = lm ? kvm->arch.xen_hvm_config.blob_addr_64 > + : kvm->arch.xen_hvm_config.blob_addr_32; > u8 blob_size = lm ? kvm->arch.xen_hvm_config.blob_size_64 > : kvm->arch.xen_hvm_config.blob_size_32; > u8 *page; > Queued, thanks. Paolo
diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c index 2cee0376455c..deda1ba8c18a 100644 --- a/arch/x86/kvm/xen.c +++ b/arch/x86/kvm/xen.c @@ -286,8 +286,12 @@ int kvm_xen_write_hypercall_page(struct kvm_vcpu *vcpu, u64 data) return 1; } } else { - u64 blob_addr = lm ? kvm->arch.xen_hvm_config.blob_addr_64 - : kvm->arch.xen_hvm_config.blob_addr_32; + /* + * Note, truncation is a non-issue as 'lm' is guaranteed to be + * false for a 32-bit kernel, i.e. when hva_t is only 4 bytes. + */ + hva_t blob_addr = lm ? kvm->arch.xen_hvm_config.blob_addr_64 + : kvm->arch.xen_hvm_config.blob_addr_32; u8 blob_size = lm ? kvm->arch.xen_hvm_config.blob_size_64 : kvm->arch.xen_hvm_config.blob_size_32; u8 *page;
Use hva_t, a.k.a. unsigned long, for the local variable that holds the hypercall page address. On 32-bit KVM, gcc complains about using a u64 due to the implicit cast from a 64-bit value to a 32-bit pointer. arch/x86/kvm/xen.c: In function ‘kvm_xen_write_hypercall_page’: arch/x86/kvm/xen.c:300:22: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast] 300 | page = memdup_user((u8 __user *)blob_addr, PAGE_SIZE); Cc: Joao Martins <joao.m.martins@oracle.com> Cc: David Woodhouse <dwmw@amazon.co.uk> Fixes: 23200b7a30de ("KVM: x86/xen: intercept xen hypercalls if enabled") Signed-off-by: Sean Christopherson <seanjc@google.com> --- arch/x86/kvm/xen.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)