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Subject[PATCH] KVM: x86/xen: Use hva_t for holding hypercall page address
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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;
--
2.30.0.478.g8a0d178c01-goog
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