Since sse instructions can issue 16-byte mmios, we need to support them. We can't increase the kvm_run mmio buffer size to 16 bytes without breaking compatibility, so instead we break the large mmios into two smaller 8-byte ones. Since the bus is 64-bit we aren't breaking any atomicity guarantees.
Signed-off-by: Avi Kivity <[email protected]> --- arch/x86/include/asm/kvm_host.h | 1 + arch/x86/kvm/x86.c | 34 +++++++++++++++++++++++++--------- include/linux/kvm_host.h | 7 ++++++- 3 files changed, 32 insertions(+), 10 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 35f81b1..e820c63 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -30,6 +30,7 @@ #define KVM_MEMORY_SLOTS 32 /* memory slots that does not exposed to userspace */ #define KVM_PRIVATE_MEM_SLOTS 4 +#define KVM_MMIO_SIZE 16 #define KVM_PIO_PAGE_OFFSET 1 #define KVM_COALESCED_MMIO_PAGE_OFFSET 2 diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 2eb1124..01aafc8 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3833,8 +3833,10 @@ mmio: vcpu->mmio_needed = 1; vcpu->run->exit_reason = KVM_EXIT_MMIO; vcpu->run->mmio.phys_addr = vcpu->mmio_phys_addr = gpa; - vcpu->run->mmio.len = vcpu->mmio_size = bytes; + vcpu->mmio_size = bytes; + vcpu->run->mmio.len = min(vcpu->mmio_size, 8); vcpu->run->mmio.is_write = vcpu->mmio_is_write = 0; + vcpu->mmio_index = 0; return X86EMUL_IO_NEEDED; } @@ -3886,11 +3888,14 @@ mmio: val += handled; vcpu->mmio_needed = 1; + memcpy(vcpu->mmio_data, val, bytes); vcpu->run->exit_reason = KVM_EXIT_MMIO; vcpu->run->mmio.phys_addr = vcpu->mmio_phys_addr = gpa; - vcpu->run->mmio.len = vcpu->mmio_size = bytes; + vcpu->mmio_size = bytes; + vcpu->run->mmio.len = min(vcpu->mmio_size, 8); vcpu->run->mmio.is_write = vcpu->mmio_is_write = 1; - memcpy(vcpu->run->mmio.data, val, bytes); + memcpy(vcpu->run->mmio.data, vcpu->mmio_data, 8); + vcpu->mmio_index = 0; return X86EMUL_CONTINUE; } @@ -4498,11 +4503,9 @@ restart: if (!vcpu->arch.pio.in) vcpu->arch.pio.count = 0; r = EMULATE_DO_MMIO; - } else if (vcpu->mmio_needed) { - if (vcpu->mmio_is_write) - vcpu->mmio_needed = 0; + } else if (vcpu->mmio_needed) r = EMULATE_DO_MMIO; - } else if (r == EMULATION_RESTART) + else if (r == EMULATION_RESTART) goto restart; else r = EMULATE_DONE; @@ -5424,9 +5427,22 @@ static int complete_mmio(struct kvm_vcpu *vcpu) return 1; if (vcpu->mmio_needed) { - memcpy(vcpu->mmio_data, run->mmio.data, 8); - vcpu->mmio_read_completed = 1; vcpu->mmio_needed = 0; + if (!vcpu->mmio_is_write) + memcpy(vcpu->mmio_data, run->mmio.data, 8); + vcpu->mmio_index += 8; + if (vcpu->mmio_index < vcpu->mmio_size) { + run->exit_reason = KVM_EXIT_MMIO; + run->mmio.phys_addr = vcpu->mmio_phys_addr + vcpu->mmio_index; + memcpy(run->mmio.data, vcpu->mmio_data + vcpu->mmio_index, 8); + run->mmio.len = min(vcpu->mmio_size - vcpu->mmio_index, 8); + run->mmio.is_write = vcpu->mmio_is_write; + vcpu->mmio_needed = 1; + return 0; + } + if (vcpu->mmio_is_write) + return 1; + vcpu->mmio_read_completed = 1; } vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu); r = emulate_instruction(vcpu, EMULTYPE_NO_DECODE); diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 57d7092..1934f48 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -27,6 +27,10 @@ #include <asm/kvm_host.h> +#ifndef KVM_MMIO_SIZE +#define KVM_MMIO_SIZE 8 +#endif + /* * vcpu->requests bit members */ @@ -133,7 +137,8 @@ struct kvm_vcpu { int mmio_read_completed; int mmio_is_write; int mmio_size; - unsigned char mmio_data[8]; + int mmio_index; + unsigned char mmio_data[KVM_MMIO_SIZE]; gpa_t mmio_phys_addr; #endif -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
